Search Results

Search found 41159 results on 1647 pages for 'incomplete type'.

Page 1/1647 | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

• When is type testing OK?

  - by svidgen

  Assuming a language with some inherent type safety (e.g., not JavaScript): Given a method that accepts a SuperType, we know that in most cases wherein we might be tempted to perform type testing to pick an action: public void DoSomethingTo(SuperType o) { if (o isa SubTypeA) { o.doSomethingA() } else { o.doSomethingB(); } } We should usually, if not always, create a single, overridable method on the SuperType and do this: public void DoSomethingTo(SuperType o) { o.doSomething(); } ... wherein each subtype is given its own doSomething() implementation. The rest of our application can then be appropriately ignorant of whether any given SuperType is really a SubTypeA or a SubTypeB. Wonderful. But, we're still given is a-like operations in most, if not all, type-safe languages. And that seems suggests a potential need for explicit type testing. So, in what situations, if any, should we or must we perform explicit type testing? Forgive my absent mindedness or lack of creativity. I know I've done it before; but, it was honestly so long ago I can't remember if what I did was good! And in recent memory, I don't think I've encountered a need to test types outside my cowboy JavaScript.

  Read the article

• kernel module compiling error

  - by wati

  sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is the location of the previous definition hello-1.c:6:0: warning: "_KERNEL_" redefined [enabled by default] <command-line>:0:0: note: this is the location of the previous definition In file included from /lib/modules/3.2.0-25-generic/build/include/linux/list.h:4:0, from /lib/modules/3.2.0-25-generic/build/include/linux/module.h:9, from hello-1.c:7: /lib/modules/3.2.0-25-generic/build/include/linux/types.h:13:2: warning: #warning "Attempt to use kernel headers from user space, see http://kernelnewbies.org/KernelHeaders" [-Wcpp] In file included from /lib/modules/3.2.0-25-generic/build/include/linux/module.h:9:0, from hello-1.c:7: /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘INIT_LIST_HEAD’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:26:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:27:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_add’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:41:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:42:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:43:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:44:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_add’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:62:28: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_add_tail’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:76:22: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:88:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:89:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_del_entry’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:101:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:101:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:106:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:106:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:107:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:108:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_replace’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:125:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:125:17: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:126:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:127:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:127:17: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:128:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_is_last’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:179:13: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_empty’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:188:13: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_empty_careful’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:206:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:207:40: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_rotate_left’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:219:15: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_is_singular’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:230:35: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:230:49: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_cut_position’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:236:37: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:237:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:237:19: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:238:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:239:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:240:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:241:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:242:11: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_cut_position’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:265:8: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_splice’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:277:32: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:278:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:280:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:281:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:283:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:284:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:296:33: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice_tail’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:308:27: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice_init’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:322:33: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice_tail_init’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:339:27: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘INIT_HLIST_NODE’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:572:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:573:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_unhashed’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:578:11: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_empty’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:583:11: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__hlist_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:588:29: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:589:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:592:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:598:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:599:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_head’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:612:30: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:613:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:615:8: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:615:20: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:616:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:617:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:617:15: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_before’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:624:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:624:17: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:625:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:626:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:626:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:627:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_after’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:633:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:633:16: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:634:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:635:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:635:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:637:9: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:638:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:638:29: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_fake’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:644:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:644:15: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_move_list’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:654:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:654:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:655:9: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:656:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:656:27: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:657:5: error: dereferencing pointer to incomplete type In file included from /lib/modules/3.2.0-25-generic/build/include/linux/module.h:12:0, from hello-1.c:7: /lib/modules/3.2.0-25-generic/build/include/linux/cache.h: At top level: /lib/modules/3.2.0-25-generic/build/include/linux/cache.h:5:23: fatal error: asm/cache.h: No such file or directory compilation terminated. make: *** [hello-1.o] Error 1 i got this error after compiling an helloworld program my program is #define MODULE #define LINUX #define _KERNEL_ #include <linux/module.h> #include <linux/kernel.h> int init_module(void) { printk("<1>hello World 1.\n"); return 0; } void cleanup_module(void) { printk(KERN_ALERT "goodbye world 1.\n"); } MODULE_LICENSE("GPL"); my make file is: TARGET := hello-1 WARN := -W -Wall -Wstrict-prototypes -Wmissing-prototypes INCLUDE := -isystem /lib/modules/`uname -r`/build/include CFLAGS := -O2 -DMODULE -D_KERNEL_ ${WARN} ${INCLUDE} CC := gcc-4.6 ${TARGET}.o: ${TARGET}.c .PHONY: clean clean: rm -rf ${TARGET}.o iam usin kernel 3.2.0.25 as novice i can't able to figure out where the problem is I SEARCHED EVERY THING I CAN TO KNOW ABOUT THIS ERROR BUT I CANT UNDERSTAND &I GET IRRELEVANT DOCS anybody help me please

  Read the article

• Type Casting variables in PHP: Is there a practical example?

  - by Stephen

  PHP, as most of us know, has weak typing. For those who don't, PHP.net says: PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used. Love it or hate it, PHP re-casts variables on-the-fly. So, the following code is valid: $var = "10"; $value = 10 + $var; var_dump($value); // int(20) PHP also alows you to explicitly cast a variable, like so: $var = "10"; $value = 10 + $var; $value = (string)$value; var_dump($value); // string(2) "20" That's all cool... but, for the life of me, I cannot conceive of a practical reason for doing this. I don't have a problem with strong typing in languages that support it, like Java. That's fine, and I completely understand it. Also, I'm aware of—and fully understand the usefulness of—type hinting in function parameters. The problem I have with type casting is explained by the above quote. If PHP can swap types at-will, it can do so even after you force cast a type; and it can do so on-the-fly when you need a certain type in an operation. That makes the following valid: $var = "10"; $value = (int)$var; $value = $value . ' TaDa!'; var_dump($value); // string(8) "10 TaDa!" So what's the point? Can anyone show me a practical application or example of type casting—one that would fail if type casting were not involved? I ask this here instead of SO because I figure practicality is too subjective. Edit in response to Chris' comment Take this theoretical example of a world where user-defined type casting makes sense in PHP: You force cast variable $foo as int -- (int)$foo. You attempt to store a string value in the variable $foo. PHP throws an exception!! <--- That would make sense. Suddenly the reason for user defined type casting exists! The fact that PHP will switch things around as needed makes the point of user defined type casting vague. For example, the following two code samples are equivalent: // example 1 $foo = 0; $foo = (string)$foo; $foo = '# of Reasons for the programmer to type cast $foo as a string: ' . $foo; // example 2 $foo = 0; $foo = (int)$foo; $foo = '# of Reasons for the programmer to type cast $foo as a string: ' . $foo;

  Read the article

• Type Casting variables in PHP: Is there a practical example?

  - by Stephen

  PHP, as most of us know, has weak typing. For those who don't, PHP.net says: PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used. Love it or hate it, PHP re-casts variables on-the-fly. So, the following code is valid: $var = "10"; $value = 10 + $var; var_dump($value); // int(20) PHP also alows you to explicitly cast a variable, like so: $var = "10"; $value = 10 + $var; $value = (string)$value; var_dump($value); // string(2) "20" That's all cool... but, for the life of me, I cannot conceive of a practical reason for doing this. I don't have a problem with strong typing in languages that support it, like Java. That's fine, and I completely understand it. Also, I'm aware of—and fully understand the usefulness of—type hinting in function parameters. The problem I have with type casting is explained by the above quote. If PHP can swap types at-will, it can do so even after you force cast a type; and it can do so on-the-fly when you need a certain type in an operation. That makes the following valid: $var = "10"; $value = (int)$var; $value = $value . ' TaDa!'; var_dump($value); // string(8) "10 TaDa!" So what's the point? Can anyone show me a practical application or example of type casting—one that would fail if type casting were not involved? I ask this here instead of SO because I figure practicality is too subjective. Edit in response to Chris' comment Take this theoretical example of a world where user-defined type casting makes sense in PHP: You force cast variable $foo as int -- (int)$foo. You attempt to store a string value in the variable $foo. PHP throws an exception!! <--- That would make sense. Suddenly the reason for user defined type casting exists! The fact that PHP will switch things around as needed makes the point of user defined type casting vague. For example, the following two code samples are equivalent: // example 1 $foo = 0; $foo = (string)$foo; $foo = '# of Reasons for the programmer to type cast $foo as a string: ' . $foo; // example 2 $foo = 0; $foo = (int)$foo; $foo = '# of Reasons for the programmer to type cast $foo as a string: ' . $foo; UPDATE Guess who found himself using typecasting in a practical environment? Yours Truly. The requirement was to display money values on a website for a restaurant menu. The design of the site required that trailing zeros be trimmed, so that the display looked something like the following: Menu Item 1 .............. $ 4 Menu Item 2 .............. $ 7.5 Menu Item 3 .............. $ 3 The best way I found to do that wast to cast the variable as a float: $price = '7.50'; // a string from the database layer. echo 'Menu Item 2 .............. $ ' . (float)$price; PHP trims the float's trailing zeros, and then recasts the float as a string for concatenation.

  Read the article

• Determining a Local File's Mime Type (Content-type) With PHP

  - by Sonny

  I am trying to determine a file's mime type. I've tried a few methods, but haven't come up with anything that gives consistent output. I've tried $mime = mime_content_type($file) and $mime = exec('file -bi ' . $file). I am serving up images, CSS, JavaScript, and images.

  Read the article

• eventmachine on debian fails install via rubygems

  - by Max

  this has been killing me for the last 5 hours. I don't seem to be able to get eventmachine running on my debian box. here this output: $ gem install thin Building native extensions. This could take a while... ERROR: Error installing thin: ERROR: Failed to build gem native extension. /home/eventhub/.rvm/rubies/ruby-1.9.3-p125/bin/ruby extconf.rb checking for rb_trap_immediate in ruby.h,rubysig.h... no checking for rb_thread_blocking_region()... yes checking for inotify_init() in sys/inotify.h... yes checking for writev() in sys/uio.h... yes checking for rb_wait_for_single_fd()... yes checking for rb_enable_interrupt()... yes checking for rb_time_new()... yes checking for sys/event.h... no checking for epoll_create() in sys/epoll.h... yes creating Makefile make compiling kb.cpp cc1plus: warning: command line option "-Wdeclaration-after-statement" is valid for C/ObjC but not for C++ cc1plus: warning: command line option "-Wimplicit-function-declaration" is valid for C/ObjC but not for C++ In file included from project.h:149, from kb.cpp:20: binder.h:35: warning: type qualifiers ignored on function return type In file included from project.h:150, from kb.cpp:20: em.h:84: warning: type qualifiers ignored on function return type em.h:85: warning: type qualifiers ignored on function return type em.h:86: warning: type qualifiers ignored on function return type em.h:88: warning: type qualifiers ignored on function return type em.h:89: warning: type qualifiers ignored on function return type em.h:90: warning: type qualifiers ignored on function return type em.h:91: warning: type qualifiers ignored on function return type em.h:93: warning: type qualifiers ignored on function return type em.h:99: warning: type qualifiers ignored on function return type em.h:116: warning: type qualifiers ignored on function return type em.h:125: warning: type qualifiers ignored on function return type In file included from project.h:154, from kb.cpp:20: eventmachine.h:46: warning: type qualifiers ignored on function return type eventmachine.h:47: warning: type qualifiers ignored on function return type eventmachine.h:48: warning: type qualifiers ignored on function return type eventmachine.h:50: warning: type qualifiers ignored on function return type eventmachine.h:65: warning: type qualifiers ignored on function return type eventmachine.h:66: warning: type qualifiers ignored on function return type eventmachine.h:67: warning: type qualifiers ignored on function return type eventmachine.h:68: warning: type qualifiers ignored on function return type In file included from project.h:154, from kb.cpp:20: eventmachine.h:103: warning: type qualifiers ignored on function return type eventmachine.h:105: warning: type qualifiers ignored on function return type eventmachine.h:108: warning: type qualifiers ignored on function return type compiling rubymain.cpp cc1plus: warning: command line option "-Wdeclaration-after-statement" is valid for C/ObjC but not for C++ cc1plus: warning: command line option "-Wimplicit-function-declaration" is valid for C/ObjC but not for C++ In file included from project.h:149, from rubymain.cpp:20: binder.h:35: warning: type qualifiers ignored on function return type In file included from project.h:150, from rubymain.cpp:20: em.h:84: warning: type qualifiers ignored on function return type em.h:85: warning: type qualifiers ignored on function return type em.h:86: warning: type qualifiers ignored on function return type em.h:88: warning: type qualifiers ignored on function return type em.h:89: warning: type qualifiers ignored on function return type em.h:90: warning: type qualifiers ignored on function return type em.h:91: warning: type qualifiers ignored on function return type em.h:93: warning: type qualifiers ignored on function return type em.h:99: warning: type qualifiers ignored on function return type em.h:116: warning: type qualifiers ignored on function return type em.h:125: warning: type qualifiers ignored on function return type In file included from project.h:154, from rubymain.cpp:20: eventmachine.h:46: warning: type qualifiers ignored on function return type eventmachine.h:47: warning: type qualifiers ignored on function return type eventmachine.h:48: warning: type qualifiers ignored on function return type eventmachine.h:50: warning: type qualifiers ignored on function return type eventmachine.h:65: warning: type qualifiers ignored on function return type eventmachine.h:66: warning: type qualifiers ignored on function return type eventmachine.h:67: warning: type qualifiers ignored on function return type eventmachine.h:68: warning: type qualifiers ignored on function return type In file included from project.h:154, from rubymain.cpp:20: eventmachine.h:103: warning: type qualifiers ignored on function return type eventmachine.h:105: warning: type qualifiers ignored on function return type eventmachine.h:108: warning: type qualifiers ignored on function return type compiling ssl.cpp cc1plus: warning: command line option "-Wdeclaration-after-statement" is valid for C/ObjC but not for C++ cc1plus: warning: command line option "-Wimplicit-function-declaration" is valid for C/ObjC but not for C++ In file included from project.h:149, from ssl.cpp:23: binder.h:35: warning: type qualifiers ignored on function return type In file included from project.h:150, from ssl.cpp:23: em.h:84: warning: type qualifiers ignored on function return type em.h:85: warning: type qualifiers ignored on function return type em.h:86: warning: type qualifiers ignored on function return type em.h:88: warning: type qualifiers ignored on function return type em.h:89: warning: type qualifiers ignored on function return type em.h:90: warning: type qualifiers ignored on function return type em.h:91: warning: type qualifiers ignored on function return type em.h:93: warning: type qualifiers ignored on function return type em.h:99: warning: type qualifiers ignored on function return type em.h:116: warning: type qualifiers ignored on function return type em.h:125: warning: type qualifiers ignored on function return type In file included from project.h:154, from ssl.cpp:23: eventmachine.h:46: warning: type qualifiers ignored on function return type eventmachine.h:47: warning: type qualifiers ignored on function return type eventmachine.h:48: warning: type qualifiers ignored on function return type eventmachine.h:50: warning: type qualifiers ignored on function return type eventmachine.h:65: warning: type qualifiers ignored on function return type eventmachine.h:66: warning: type qualifiers ignored on function return type eventmachine.h:67: warning: type qualifiers ignored on function return type eventmachine.h:68: warning: type qualifiers ignored on function return type In file included from project.h:154, from ssl.cpp:23: eventmachine.h:103: warning: type qualifiers ignored on function return type eventmachine.h:105: warning: type qualifiers ignored on function return type eventmachine.h:108: warning: type qualifiers ignored on function return type compiling cmain.cpp cc1plus: warning: command line option "-Wdeclaration-after-statement" is valid for C/ObjC but not for C++ cc1plus: warning: command line option "-Wimplicit-function-declaration" is valid for C/ObjC but not for C++ In file included from project.h:149, from cmain.cpp:20: binder.h:35: warning: type qualifiers ignored on function return type In file included from project.h:150, from cmain.cpp:20: em.h:84: warning: type qualifiers ignored on function return type em.h:85: warning: type qualifiers ignored on function return type em.h:86: warning: type qualifiers ignored on function return type em.h:88: warning: type qualifiers ignored on function return type em.h:89: warning: type qualifiers ignored on function return type em.h:90: warning: type qualifiers ignored on function return type em.h:91: warning: type qualifiers ignored on function return type em.h:93: warning: type qualifiers ignored on function return type em.h:99: warning: type qualifiers ignored on function return type em.h:116: warning: type qualifiers ignored on function return type em.h:125: warning: type qualifiers ignored on function return type In file included from project.h:154, from cmain.cpp:20: eventmachine.h:46: warning: type qualifiers ignored on function return type eventmachine.h:47: warning: type qualifiers ignored on function return type eventmachine.h:48: warning: type qualifiers ignored on function return type eventmachine.h:50: warning: type qualifiers ignored on function return type eventmachine.h:65: warning: type qualifiers ignored on function return type eventmachine.h:66: warning: type qualifiers ignored on function return type eventmachine.h:67: warning: type qualifiers ignored on function return type eventmachine.h:68: warning: type qualifiers ignored on function return type In file included from project.h:154, from cmain.cpp:20: eventmachine.h:103: warning: type qualifiers ignored on function return type eventmachine.h:105: warning: type qualifiers ignored on function return type eventmachine.h:108: warning: type qualifiers ignored on function return type cmain.cpp:96: warning: type qualifiers ignored on function return type cmain.cpp:107: warning: type qualifiers ignored on function return type cmain.cpp:117: warning: type qualifiers ignored on function return type cmain.cpp:127: warning: type qualifiers ignored on function return type cmain.cpp:269: warning: type qualifiers ignored on function return type cmain.cpp:279: warning: type qualifiers ignored on function return type cmain.cpp:289: warning: type qualifiers ignored on function return type cmain.cpp:299: warning: type qualifiers ignored on function return type cmain.cpp:309: warning: type qualifiers ignored on function return type cmain.cpp:329: warning: type qualifiers ignored on function return type cmain.cpp:678: warning: type qualifiers ignored on function return type compiling em.cpp cc1plus: warning: command line option "-Wdeclaration-after-statement" is valid for C/ObjC but not for C++ cc1plus: warning: command line option "-Wimplicit-function-declaration" is valid for C/ObjC but not for C++ In file included from project.h:149, from em.cpp:23: binder.h:35: warning: type qualifiers ignored on function return type In file included from project.h:150, from em.cpp:23: em.h:84: warning: type qualifiers ignored on function return type em.h:85: warning: type qualifiers ignored on function return type em.h:86: warning: type qualifiers ignored on function return type em.h:88: warning: type qualifiers ignored on function return type em.h:89: warning: type qualifiers ignored on function return type em.h:90: warning: type qualifiers ignored on function return type em.h:91: warning: type qualifiers ignored on function return type em.h:93: warning: type qualifiers ignored on function return type em.h:99: warning: type qualifiers ignored on function return type em.h:116: warning: type qualifiers ignored on function return type em.h:125: warning: type qualifiers ignored on function return type In file included from project.h:154, from em.cpp:23: eventmachine.h:46: warning: type qualifiers ignored on function return type eventmachine.h:47: warning: type qualifiers ignored on function return type eventmachine.h:48: warning: type qualifiers ignored on function return type eventmachine.h:50: warning: type qualifiers ignored on function return type eventmachine.h:65: warning: type qualifiers ignored on function return type eventmachine.h:66: warning: type qualifiers ignored on function return type eventmachine.h:67: warning: type qualifiers ignored on function return type eventmachine.h:68: warning: type qualifiers ignored on function return type In file included from project.h:154, from em.cpp:23: eventmachine.h:103: warning: type qualifiers ignored on function return type eventmachine.h:105: warning: type qualifiers ignored on function return type eventmachine.h:108: warning: type qualifiers ignored on function return type em.cpp: In member function 'bool EventMachine_t::_RunEpollOnce()': em.cpp:578: warning: 'int rb_thread_select(int, fd_set*, fd_set*, fd_set*, timeval*)' is deprecated (declared at /home/eventhub/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/intern.h:379) em.cpp:578: warning: 'int rb_thread_select(int, fd_set*, fd_set*, fd_set*, timeval*)' is deprecated (declared at /home/eventhub/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/intern.h:379) em.cpp: In member function 'bool EventMachine_t::_RunSelectOnce()': em.cpp:974: warning: 'int rb_thread_select(int, fd_set*, fd_set*, fd_set*, timeval*)' is deprecated (declared at /home/eventhub/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/intern.h:379) em.cpp:974: warning: 'int rb_thread_select(int, fd_set*, fd_set*, fd_set*, timeval*)' is deprecated (declared at /home/eventhub/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/intern.h:379) em.cpp: At global scope: em.cpp:1057: warning: type qualifiers ignored on function return type em.cpp:1079: warning: type qualifiers ignored on function return type em.cpp:1265: warning: type qualifiers ignored on function return type em.cpp:1338: warning: type qualifiers ignored on function return type em.cpp:1510: warning: type qualifiers ignored on function return type em.cpp:1593: warning: type qualifiers ignored on function return type em.cpp:1856: warning: type qualifiers ignored on function return type em.cpp:1982: warning: type qualifiers ignored on function return type em.cpp:2046: warning: type qualifiers ignored on function return type em.cpp:2070: warning: type qualifiers ignored on function return type em.cpp:2142: warning: type qualifiers ignored on function return type em.cpp:2361: fatal error: error writing to /tmp/ccdlOK0T.s: No space left on device compilation terminated. make: *** [em.o] Error 1 Gem files will remain installed in /home/eventhub/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-1.0.1 for inspection. Results logged to /home/eventhub/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-1.0.1/ext/gem_make.out Any thoughts? I read a lot of different ways to solve this issue, but none of them worked. Thanks

  Read the article

• Type checking and recursive types (Writing the Y combinator in Haskell/Ocaml)

  - by beta

  When explaining the Y combinator in the context of Haskell, it's usually noted that the straight-forward implementation won't type-check in Haskell because of its recursive type. For example, from Rosettacode [1]: The obvious definition of the Y combinator in Haskell canot be used because it contains an infinite recursive type (a = a -> b). Defining a data type (Mu) allows this recursion to be broken. newtype Mu a = Roll { unroll :: Mu a -> a } fix :: (a -> a) -> a fix = \f -> (\x -> f (unroll x x)) $ Roll (\x -> f (unroll x x)) And indeed, the “obvious” definition does not type check: ?> let fix f g = (\x -> \a -> f (x x) a) (\x -> \a -> f (x x) a) g <interactive>:10:33: Occurs check: cannot construct the infinite type: t2 = t2 -> t0 -> t1 Expected type: t2 -> t0 -> t1 Actual type: (t2 -> t0 -> t1) -> t0 -> t1 In the first argument of `x', namely `x' In the first argument of `f', namely `(x x)' In the expression: f (x x) a <interactive>:10:57: Occurs check: cannot construct the infinite type: t2 = t2 -> t0 -> t1 In the first argument of `x', namely `x' In the first argument of `f', namely `(x x)' In the expression: f (x x) a (0.01 secs, 1033328 bytes) The same limitation exists in Ocaml: utop # let fix f g = (fun x a -> f (x x) a) (fun x a -> f (x x) a) g;; Error: This expression has type 'a -> 'b but an expression was expected of type 'a The type variable 'a occurs inside 'a -> 'b However, in Ocaml, one can allow recursive types by passing in the -rectypes switch: -rectypes Allow arbitrary recursive types during type-checking. By default, only recursive types where the recursion goes through an object type are supported. By using -rectypes, everything works: utop # let fix f g = (fun x a -> f (x x) a) (fun x a -> f (x x) a) g;; val fix : (('a -> 'b) -> 'a -> 'b) -> 'a -> 'b = <fun> utop # let fact_improver partial n = if n = 0 then 1 else n*partial (n-1);; val fact_improver : (int -> int) -> int -> int = <fun> utop # (fix fact_improver) 5;; - : int = 120 Being curious about type systems and type inference, this raises some questions I'm still not able to answer. First, how does the type checker come up with the type t2 = t2 -> t0 -> t1? Having come up with that type, I guess the problem is that the type (t2) refers to itself on the right side? Second, and perhaps most interesting, what is the reason for the Haskell/Ocaml type systems to disallow this? I guess there is a good reason since Ocaml also will not allow it by default even if it can deal with recursive types if given the -rectypes switch. If these are really big topics, I'd appreciate pointers to relevant literature. [1] http://rosettacode.org/wiki/Y_combinator#Haskell

  Read the article

• How to allow bind in app armor?

  - by WitchCraft

  Question: I did setup bind9 as described here: http://ubuntuforums.org/showthread.php?p=12149576#post12149576 Now I have a little problem with apparmor: If I switch it off, it works. If apparmor runs, it doesn't work, and I get the following dmesg output: [ 23.809767] type=1400 audit(1344097913.519:11): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=1540 comm="apparmor_parser" [ 23.811537] type=1400 audit(1344097913.519:12): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=1540 comm="apparmor_parser" [ 23.812514] type=1400 audit(1344097913.523:13): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=1540 comm="apparmor_parser" [ 23.821999] type=1400 audit(1344097913.531:14): apparmor="STATUS" operation="profile_load" name="/usr/sbin/mysqld" pid=1544 comm="apparmor_parser" [ 23.845085] type=1400 audit(1344097913.555:15): apparmor="STATUS" operation="profile_load" name="/usr/sbin/libvirtd" pid=1543 comm="apparmor_parser" [ 23.849051] type=1400 audit(1344097913.559:16): apparmor="STATUS" operation="profile_load" name="/usr/sbin/named" pid=1545 comm="apparmor_parser" [ 23.849509] type=1400 audit(1344097913.559:17): apparmor="STATUS" operation="profile_load" name="/usr/lib/libvirt/virt-aa-helper" pid=1542 comm="apparmor_parser" [ 23.851597] type=1400 audit(1344097913.559:18): apparmor="STATUS" operation="profile_load" name="/usr/sbin/tcpdump" pid=1547 comm="apparmor_parser" [ 24.415193] type=1400 audit(1344097914.123:19): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/mysqld" pid=1625 comm="apparmor_parser" [ 24.738631] ip_tables: (C) 2000-2006 Netfilter Core Team [ 25.005242] nf_conntrack version 0.5.0 (16384 buckets, 65536 max) [ 25.187939] ADDRCONF(NETDEV_UP): virbr0: link is not ready [ 26.004282] Ebtables v2.0 registered [ 26.068783] ip6_tables: (C) 2000-2006 Netfilter Core Team [ 28.158848] postgres (1900): /proc/1900/oom_adj is deprecated, please use /proc/1900/oom_score_adj instead. [ 29.840079] xenbr0: no IPv6 routers present [ 31.502916] type=1400 audit(1344097919.088:20): apparmor="DENIED" operation="mknod" parent=1984 profile="/usr/sbin/named" name="/var/log/query.log" pid=1989 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 34.336141] xenbr0: port 1(eth0) entering forwarding state [ 38.424359] Event-channel device installed. [ 38.853077] XENBUS: Unable to read cpu state [ 38.854215] XENBUS: Unable to read cpu state [ 38.855231] XENBUS: Unable to read cpu state [ 38.858891] XENBUS: Unable to read cpu state [ 47.411497] device vif1.0 entered promiscuous mode [ 47.429245] ADDRCONF(NETDEV_UP): vif1.0: link is not ready [ 49.366219] virbr0: port 1(vif1.0) entering disabled state [ 49.366705] virbr0: port 1(vif1.0) entering disabled state [ 49.368873] virbr0: mixed no checksumming and other settings. [ 97.273028] type=1400 audit(1344097984.861:21): apparmor="DENIED" operation="mknod" parent=3076 profile="/usr/sbin/named" name="/var/log/query.log" pid=3078 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 277.790627] type=1400 audit(1344098165.377:22): apparmor="DENIED" operation="mknod" parent=3384 profile="/usr/sbin/named" name="/var/log/query.log" pid=3389 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 287.812986] type=1400 audit(1344098175.401:23): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/root/tmp-gjnX0c0dDa" pid=3400 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 287.818466] type=1400 audit(1344098175.405:24): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/root/tmp-CpOtH52qU5" pid=3400 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 323.166228] type=1400 audit(1344098210.753:25): apparmor="DENIED" operation="mknod" parent=3422 profile="/usr/sbin/named" name="/var/log/query.log" pid=3427 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 386.512586] type=1400 audit(1344098274.101:26): apparmor="DENIED" operation="mknod" parent=3456 profile="/usr/sbin/named" name="/var/log/query.log" pid=3459 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 808.549049] type=1400 audit(1344098696.137:27): apparmor="DENIED" operation="mknod" parent=3872 profile="/usr/sbin/named" name="/var/log/query.log" pid=3877 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 894.671081] type=1400 audit(1344098782.257:28): apparmor="DENIED" operation="mknod" parent=3922 profile="/usr/sbin/named" name="/var/log/query.log" pid=3927 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 968.514669] type=1400 audit(1344098856.101:29): apparmor="DENIED" operation="mknod" parent=3978 profile="/usr/sbin/named" name="/var/log/query.log" pid=3983 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1021.814582] type=1400 audit(1344098909.401:30): apparmor="DENIED" operation="mknod" parent=4010 profile="/usr/sbin/named" name="/var/log/query.log" pid=4012 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1063.856633] type=1400 audit(1344098951.445:31): apparmor="DENIED" operation="mknod" parent=4041 profile="/usr/sbin/named" name="/var/log/query.log" pid=4043 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1085.404001] type=1400 audit(1344098972.989:32): apparmor="DENIED" operation="mknod" parent=4072 profile="/usr/sbin/named" name="/var/log/query.log" pid=4077 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1108.207402] type=1400 audit(1344098995.793:33): apparmor="DENIED" operation="mknod" parent=4102 profile="/usr/sbin/named" name="/var/log/query.log" pid=4107 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1156.947189] type=1400 audit(1344099044.533:34): apparmor="DENIED" operation="mknod" parent=4134 profile="/usr/sbin/named" name="/var/log/query.log" pid=4136 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1166.768005] type=1400 audit(1344099054.353:35): apparmor="DENIED" operation="mknod" parent=4150 profile="/usr/sbin/named" name="/var/log/query.log" pid=4155 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1168.873385] type=1400 audit(1344099056.461:36): apparmor="DENIED" operation="mknod" parent=4162 profile="/usr/sbin/named" name="/var/log/query.log" pid=4167 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1181.558946] type=1400 audit(1344099069.145:37): apparmor="DENIED" operation="mknod" parent=4177 profile="/usr/sbin/named" name="/var/log/query.log" pid=4182 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 1199.349265] type=1400 audit(1344099086.937:38): apparmor="DENIED" operation="mknod" parent=4191 profile="/usr/sbin/named" name="/var/log/query.log" pid=4196 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 1296.805604] type=1400 audit(1344099184.393:39): apparmor="DENIED" operation="mknod" parent=4232 profile="/usr/sbin/named" name="/var/log/query.log" pid=4237 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1317.730568] type=1400 audit(1344099205.317:40): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/tmp-nuBes0IXwi" pid=4251 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1317.730744] type=1400 audit(1344099205.317:41): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/tmp-ZDJA06ZOkU" pid=4252 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1365.072687] type=1400 audit(1344099252.661:42): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/tmp-EnsuYUrGOC" pid=4290 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1365.074520] type=1400 audit(1344099252.661:43): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/tmp-LVCnpWOStP" pid=4287 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1380.336984] type=1400 audit(1344099267.925:44): apparmor="DENIED" operation="mknod" parent=4617 profile="/usr/sbin/named" name="/var/log/query.log" pid=4622 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1437.924534] type=1400 audit(1344099325.513:45): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/tmp-Uyf1dHIZUU" pid=4648 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1437.924626] type=1400 audit(1344099325.513:46): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/tmp-OABXWclII3" pid=4647 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1526.334959] type=1400 audit(1344099413.921:47): apparmor="DENIED" operation="mknod" parent=4749 profile="/usr/sbin/named" name="/var/log/query.log" pid=4754 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 1601.292548] type=1400 audit(1344099488.881:48): apparmor="DENIED" operation="mknod" parent=4835 profile="/usr/sbin/named" name="/var/log/query.log" pid=4840 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 1639.543733] type=1400 audit(1344099527.129:49): apparmor="DENIED" operation="mknod" parent=4905 profile="/usr/sbin/named" name="/var/log/query.log" pid=4907 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1916.381179] type=1400 audit(1344099803.969:50): apparmor="DENIED" operation="mknod" parent=4959 profile="/usr/sbin/named" name="/var/log/query.log" pid=4961 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 1940.816898] type=1400 audit(1344099828.405:51): apparmor="DENIED" operation="mknod" parent=4991 profile="/usr/sbin/named" name="/var/log/query.log" pid=4996 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 2043.010898] type=1400 audit(1344099930.597:52): apparmor="DENIED" operation="mknod" parent=5048 profile="/usr/sbin/named" name="/var/log/query.log" pid=5053 comm="named" requested_mask="c" denied_mask="c" fsuid=107 ouid=107 [ 2084.956230] type=1400 audit(1344099972.545:53): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/var/log/tmp-XYgr33RqUt" pid=5069 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 2084.959120] type=1400 audit(1344099972.545:54): apparmor="DENIED" operation="mknod" parent=3325 profile="/usr/sbin/named" name="/var/log/tmp-vO24RHwL14" pid=5066 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 2088.169500] type=1400 audit(1344099975.757:55): apparmor="DENIED" operation="mknod" parent=5076 profile="/usr/sbin/named" name="/var/log/query.log" pid=5078 comm="named" requested_mask="c" denied_mask="c" fsuid=0 ouid=0 [ 2165.625096] type=1400 audit(1344100053.213:56): apparmor="STATUS" operation="profile_remove" name="/sbin/dhclient" pid=5124 comm="apparmor" [ 2165.625401] type=1400 audit(1344100053.213:57): apparmor="STATUS" operation="profile_remove" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=5124 comm="apparmor" [ 2165.625608] type=1400 audit(1344100053.213:58): apparmor="STATUS" operation="profile_remove" name="/usr/lib/connman/scripts/dhclient-script" pid=5124 comm="apparmor" [ 2165.625782] type=1400 audit(1344100053.213:59): apparmor="STATUS" operation="profile_remove" name="/usr/lib/libvirt/virt-aa-helper" pid=5124 comm="apparmor" [ 2165.625931] type=1400 audit(1344100053.213:60): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/libvirtd" pid=5124 comm="apparmor" [ 2165.626057] type=1400 audit(1344100053.213:61): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/mysqld" pid=5124 comm="apparmor" [ 2165.626181] type=1400 audit(1344100053.213:62): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/named" pid=5124 comm="apparmor" [ 2165.626319] type=1400 audit(1344100053.213:63): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/tcpdump" pid=5124 comm="apparmor" [ 3709.583927] type=1400 audit(1344101597.169:64): apparmor="STATUS" operation="profile_load" name="/usr/sbin/libvirtd" pid=7484 comm="apparmor_parser" [ 3709.839895] type=1400 audit(1344101597.425:65): apparmor="STATUS" operation="profile_load" name="/usr/sbin/mysqld" pid=7485 comm="apparmor_parser" [ 3710.008892] type=1400 audit(1344101597.597:66): apparmor="STATUS" operation="profile_load" name="/usr/lib/libvirt/virt-aa-helper" pid=7483 comm="apparmor_parser" [ 3710.545232] type=1400 audit(1344101598.133:67): apparmor="STATUS" operation="profile_load" name="/usr/sbin/named" pid=7486 comm="apparmor_parser" [ 3710.655600] type=1400 audit(1344101598.241:68): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=7481 comm="apparmor_parser" [ 3710.656013] type=1400 audit(1344101598.241:69): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=7481 comm="apparmor_parser" [ 3710.656786] type=1400 audit(1344101598.245:70): apparmor="STATUS" operation="profile_load" name="/usr/lib/connman/scripts/dhclient-script" pid=7481 comm="apparmor_parser" [ 3710.832624] type=1400 audit(1344101598.421:71): apparmor="STATUS" operation="profile_load" name="/usr/sbin/tcpdump" pid=7488 comm="apparmor_parser" [ 3717.573123] type=1400 audit(1344101605.161:72): apparmor="DENIED" operation="open" parent=7505 profile="/usr/sbin/named" name="/var/log/query.log" pid=7510 comm="named" requested_mask="ac" denied_mask="ac" fsuid=107 ouid=0 [ 3743.667808] type=1400 audit(1344101631.253:73): apparmor="STATUS" operation="profile_remove" name="/sbin/dhclient" pid=7552 comm="apparmor" [ 3743.668338] type=1400 audit(1344101631.257:74): apparmor="STATUS" operation="profile_remove" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=7552 comm="apparmor" [ 3743.668625] type=1400 audit(1344101631.257:75): apparmor="STATUS" operation="profile_remove" name="/usr/lib/connman/scripts/dhclient-script" pid=7552 comm="apparmor" [ 3743.668834] type=1400 audit(1344101631.257:76): apparmor="STATUS" operation="profile_remove" name="/usr/lib/libvirt/virt-aa-helper" pid=7552 comm="apparmor" [ 3743.668991] type=1400 audit(1344101631.257:77): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/libvirtd" pid=7552 comm="apparmor" [ 3743.669127] type=1400 audit(1344101631.257:78): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/mysqld" pid=7552 comm="apparmor" [ 3743.669282] type=1400 audit(1344101631.257:79): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/named" pid=7552 comm="apparmor" [ 3743.669520] type=1400 audit(1344101631.257:80): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/tcpdump" pid=7552 comm="apparmor" [ 3873.572336] type=1400 audit(1344101761.161:81): apparmor="STATUS" operation="profile_load" name="/usr/sbin/libvirtd" pid=7722 comm="apparmor_parser" [ 3873.826209] type=1400 audit(1344101761.413:82): apparmor="STATUS" operation="profile_load" name="/usr/sbin/mysqld" pid=7723 comm="apparmor_parser" [ 3873.988181] type=1400 audit(1344101761.577:83): apparmor="STATUS" operation="profile_load" name="/usr/lib/libvirt/virt-aa-helper" pid=7721 comm="apparmor_parser" [ 3874.520305] type=1400 audit(1344101762.109:84): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=7719 comm="apparmor_parser" [ 3874.520736] type=1400 audit(1344101762.109:85): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=7719 comm="apparmor_parser" [ 3874.521000] type=1400 audit(1344101762.109:86): apparmor="STATUS" operation="profile_load" name="/usr/lib/connman/scripts/dhclient-script" pid=7719 comm="apparmor_parser" [ 3874.528878] type=1400 audit(1344101762.117:87): apparmor="STATUS" operation="profile_load" name="/usr/sbin/named" pid=7724 comm="apparmor_parser" [ 3874.930712] type=1400 audit(1344101762.517:88): apparmor="STATUS" operation="profile_load" name="/usr/sbin/tcpdump" pid=7726 comm="apparmor_parser" [ 3971.744599] type=1400 audit(1344101859.333:89): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/libvirtd" pid=7899 comm="apparmor_parser" [ 3972.009857] type=1400 audit(1344101859.597:90): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/mysqld" pid=7900 comm="apparmor_parser" [ 3972.165297] type=1400 audit(1344101859.753:91): apparmor="STATUS" operation="profile_replace" name="/usr/lib/libvirt/virt-aa-helper" pid=7898 comm="apparmor_parser" [ 3972.587766] type=1400 audit(1344101860.173:92): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/named" pid=7901 comm="apparmor_parser" [ 3972.847189] type=1400 audit(1344101860.433:93): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=7896 comm="apparmor_parser" [ 3972.847705] type=1400 audit(1344101860.433:94): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=7896 comm="apparmor_parser" [ 3972.848150] type=1400 audit(1344101860.433:95): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=7896 comm="apparmor_parser" [ 3973.147889] type=1400 audit(1344101860.733:96): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/tcpdump" pid=7903 comm="apparmor_parser" [ 3988.863999] type=1400 audit(1344101876.449:97): apparmor="DENIED" operation="open" parent=7939 profile="/usr/sbin/named" name="/var/log/query.log" pid=7944 comm="named" requested_mask="ac" denied_mask="ac" fsuid=107 ouid=0 [ 4025.826132] type=1400 audit(1344101913.413:98): apparmor="STATUS" operation="profile_remove" name="/sbin/dhclient" pid=7975 comm="apparmor" [ 4025.826627] type=1400 audit(1344101913.413:99): apparmor="STATUS" operation="profile_remove" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=7975 comm="apparmor" [ 4025.826861] type=1400 audit(1344101913.413:100): apparmor="STATUS" operation="profile_remove" name="/usr/lib/connman/scripts/dhclient-script" pid=7975 comm="apparmor" [ 4025.827059] type=1400 audit(1344101913.413:101): apparmor="STATUS" operation="profile_remove" name="/usr/lib/libvirt/virt-aa-helper" pid=7975 comm="apparmor" [ 4025.827214] type=1400 audit(1344101913.413:102): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/libvirtd" pid=7975 comm="apparmor" [ 4025.827352] type=1400 audit(1344101913.413:103): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/mysqld" pid=7975 comm="apparmor" [ 4025.827485] type=1400 audit(1344101913.413:104): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/named" pid=7975 comm="apparmor" [ 4025.827624] type=1400 audit(1344101913.413:105): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/tcpdump" pid=7975 comm="apparmor" [ 4027.862198] type=1400 audit(1344101915.449:106): apparmor="STATUS" operation="profile_load" name="/usr/sbin/libvirtd" pid=8090 comm="apparmor_parser" [ 4039.500920] audit_printk_skb: 21 callbacks suppressed [ 4039.500932] type=1400 audit(1344101927.089:114): apparmor="STATUS" operation="profile_remove" name="/sbin/dhclient" pid=8114 comm="apparmor" [ 4039.501413] type=1400 audit(1344101927.089:115): apparmor="STATUS" operation="profile_remove" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=8114 comm="apparmor" [ 4039.501672] type=1400 audit(1344101927.089:116): apparmor="STATUS" operation="profile_remove" name="/usr/lib/connman/scripts/dhclient-script" pid=8114 comm="apparmor" [ 4039.501861] type=1400 audit(1344101927.089:117): apparmor="STATUS" operation="profile_remove" name="/usr/lib/libvirt/virt-aa-helper" pid=8114 comm="apparmor" [ 4039.502033] type=1400 audit(1344101927.089:118): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/libvirtd" pid=8114 comm="apparmor" [ 4039.502170] type=1400 audit(1344101927.089:119): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/mysqld" pid=8114 comm="apparmor" [ 4039.502305] type=1400 audit(1344101927.089:120): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/named" pid=8114 comm="apparmor" [ 4039.502442] type=1400 audit(1344101927.089:121): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/tcpdump" pid=8114 comm="apparmor" [ 4041.425405] type=1400 audit(1344101929.013:122): apparmor="STATUS" operation="profile_load" name="/usr/lib/libvirt/virt-aa-helper" pid=8240 comm="apparmor_parser" [ 4041.425952] type=1400 audit(1344101929.013:123): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=8238 comm="apparmor_parser" [ 4058.910390] audit_printk_skb: 18 callbacks suppressed [ 4058.910401] type=1400 audit(1344101946.497:130): apparmor="STATUS" operation="profile_remove" name="/sbin/dhclient" pid=8264 comm="apparmor" [ 4058.910757] type=1400 audit(1344101946.497:131): apparmor="STATUS" operation="profile_remove" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=8264 comm="apparmor" [ 4058.910969] type=1400 audit(1344101946.497:132): apparmor="STATUS" operation="profile_remove" name="/usr/lib/connman/scripts/dhclient-script" pid=8264 comm="apparmor" [ 4058.911185] type=1400 audit(1344101946.497:133): apparmor="STATUS" operation="profile_remove" name="/usr/lib/libvirt/virt-aa-helper" pid=8264 comm="apparmor" [ 4058.911335] type=1400 audit(1344101946.497:134): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/libvirtd" pid=8264 comm="apparmor" [ 4058.911595] type=1400 audit(1344101946.497:135): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/mysqld" pid=8264 comm="apparmor" [ 4058.911856] type=1400 audit(1344101946.497:136): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/named" pid=8264 comm="apparmor" [ 4058.912001] type=1400 audit(1344101946.497:137): apparmor="STATUS" operation="profile_remove" name="/usr/sbin/tcpdump" pid=8264 comm="apparmor" [ 4060.266700] type=1400 audit(1344101947.853:138): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=8391 comm="apparmor_parser" [ 4060.268356] type=1400 audit(1344101947.857:139): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=8391 comm="apparmor_parser" [ 5909.432749] audit_printk_skb: 18 callbacks suppressed [ 5909.432759] type=1400 audit(1344103797.021:146): apparmor="DENIED" operation="open" parent=8800 profile="/usr/sbin/named" name="/var/log/query.log" pid=8805 comm="named" requested_mask="ac" denied_mask="ac" fsuid=107 ouid=0 root@zotac:~# What can I do that it still works and I don't have to disable apparmor ?

  Read the article

• What are the safety benefits of a type system?

  - by vandros526

  In Javascript: The Good Parts by Douglas Crockford, he mentions in his inheritance chapter, "The other benefit of classical inheritance is that it includes the specification of a system of types. This mostly frees the programmer from having to write explicit casting operations, which is a very good thing because when casting, the safety benefits of a type system are lost." So first of all, what actually is safety? protection against data corruption, or hackers, or system malfunctions, etc? What are the safety benefits of a type system? What makes a type system different that allows it to provide these safety benefits?

  Read the article

• Converting Generic Type into reference type after checking its type using GetType(). How ?

  - by Shantanu Gupta

  i am trying to call a function that is defined in a class RFIDeas_Wrapper(dll being used). But when i checked for type of reader and after that i used it to call function it shows me error Cannot convert type T to RFIDeas_Wrapper. EDIT private List<string> GetTagCollection<T>(T Reader) { TagCollection = new List<string>(); if (Reader.GetType() == typeof(RFIDeas_Wrapper)) { ((RFIDeas_Wrapper)Reader).OpenDevice(); // here Reader is of type RFIDeas_Wrapper //, but i m not able to convert Reader into its datatype. string Tag_Id = ((RFIDeas_Wrapper)Reader).TagID(); //Adds Valid Tag Ids into the collection if(Tag_Id!="0") TagCollection.Add(Tag_Id); } else if (Reader.GetType() == typeof(AlienReader)) TagCollection = ((AlienReader)Reader).TagCollection; return TagCollection; } ((RFIDeas_Wrapper)Reader).OpenDevice(); , ((AlienReader)Reader).TagCollection; I want this line to be executed without any issue. As Reader will always be of the type i m specifying. How to make compiler understand the same thing.

  Read the article

• Type dependencies vs directory structure

  - by paul

  Something I've been wondering about recently is how to organize types in directories/namespaces w.r.t. their dependencies. One method I've seen, which I believe is the recommendation for both Haskell and .NET (though I can't find the references for this at the moment), is: Type Type/ATypeThatUsesType Type/AnotherTypeThatUsesType My natural inclination, however, is to do the opposite: Type Type/ATypeUponWhichTypeDepends Type/AnotherTypeUponWhichTypeDepends Questions: Is my inclination bass-ackwards? Are there any major benefits/pitfalls of one over the other? Is it just something that depends on the application, e.g. whether you're building a library vs doing normal coding?

  Read the article

• Accessing type-parameter of a type-parameter

  - by itemState

  i would like to access, in a trait, the type-parameter of a type-parameter of that trait. without adding this "second-order" type-parameter as another "first-order" parameter to the trait. the following illustrates this problem: sealed trait A; sealed trait A1 extends A; sealed trait A2 extends A trait B[ ASpecific <: A ] { type ASpec = ASpecific } trait D[ ASpecific <: A ] extends B[ ASpecific ] trait C[ +BSpecific <: B[ _ <: A ]] { def unaryOp : C[ D[ BSpecific#ASpec ]] } def test( c: C[ B[ A1 ]]) : C[ D[ A1 ]] = c.unaryOp the test fails to compile because apparently, the c.unaryOp has a result of type C[D[A]] and not C[D[A1]], indicating that ASpec is merely a shortcut for _ <: A and does not refer to the specific type parameter. the two-type-parameter solution is simple: sealed trait A; sealed trait A1 extends A; sealed trait A2 extends A trait B[ ASpecific <: A ] trait D[ ASpecific <: A ] extends B[ ASpecific ] trait C[ ASpecific <: A, +BSpecific <: B[ ASpecific ]] { def unaryOp : C[ ASpecific, D[ ASpecific ]] } def test( c: C[ A1, B[ A1 ]]) : C[ A1, D[ A1 ]] = c.unaryOp but i don't understand why i need to clutter my source with this second, obviously redundant, parameter. is there no way to retrieve it from trait B?

  Read the article

• Change type of control by type

  - by Ruben

  Hi, I'm having following problem. I should convert a control to a certain type, this can be multiple types (for example a custom button or a custom label, ....) Here's an example of what i would like to do: private void ConvertToTypeAndUseCustomProperty(Control c) { Type type = c.getType(); ((type) c).CustomPropertieOfControl = 234567; } Thanks in advance.

  Read the article

• IIS website is sending multiple content-type headers for zip files

  - by frankadelic

  We have a problem with an IIS5 server. When certain users/browsers click to download .zip files, binary gibberish text sometimes renders in the browser window. The desired behavior is for the file to either download or open with the associated zip application. Initially, we suspected that the wrong content-type header was set on the file. The IIS tech confirmed that .zip files were being served by IIS with the mime-type "application/x-zip-compressed". However, an inspection of the HTTP packets using Wireshark reveals that requests for zip files return two Content-Type headers. Content-Type: text/html; charset=UTF-8 Content-Type: application/x-zip-compressed Any idea why IIS is sending two content-type headers? This doesn't happen for regular HTML or images files. It does happen with ZIP and PDF. Is there a particular place we can ask the IIS tech to look? Or is there a configuration file we can examine?

  Read the article

• Converting raw data type to enumerated type

  - by Jim Lahman

  There are times when an enumerated type is preferred over using the raw data type.  An example of using a scheme is when we need to check the health of x-ray gauges in use on a production line.  Rather than using a scheme like 0, 1 and 2, we can use an enumerated type: 1: /// <summary> 2: /// POR Healthy status indicator 3: /// </summary> 4: /// <remarks>The healthy status is for each POR x-ray gauge; each has its own status.</remarks> 5: [Flags] 6: public enum POR_HEALTH : short 7: { 8: /// <summary> 9: /// POR1 healthy status indicator 10: /// </summary> 11: POR1 = 0, 12: /// <summary> 13: /// POR2 healthy status indicator 14: /// </summary> 15: POR2 = 1, 16: /// <summary> 17: /// Both POR1 and POR2 healthy status indicator 18: /// </summary> 19: BOTH = 2 20: } By using the [Flags] attribute, we are treating the enumerated type as a bit mask.  We can then use bitwise operations such as AND, OR, NOT etc. . Now, when we want to check the health of a specific gauge, we would rather use the name of the gauge than the numeric identity; it makes for better reading and programming practice. To translate the numeric identity to the enumerated value, we use the Parse method of Enum class: POR_HEALTH GaugeHealth = (POR_HEALTH) Enum.Parse(typeof(POR_HEALTH), XrayMsg.Gauge_ID.ToString()); The Parse method creates an instance of the enumerated type.  Now, we can use the name of the gauge rather than the numeric identity: 1: if (GaugeHealth == POR_HEALTH.POR1 || GaugeHealth == POR_HEALTH.BOTH) 2: { 3: XrayHealthyTag.Name = Properties.Settings.Default.POR1XRayHealthyTag; 4: } 5: else if (GaugeHealth == POR_HEALTH.POR2) 6: { 7: XrayHealthyTag.Name = Properties.Settings.Default.POR2XRayHealthyTag; 8: }

  Read the article

• Why to say, my function is of IFly type rather than saying it's Airplane type

  - by Vishwas Gagrani

  Say, I have two classes: Airplane and Bird, both of them fly. Both implement the interface IFly. IFly declares a function StartFlying(). Thus both Airplane and Bird have to define the function, and use it as per their requirement. Now when I make a manual for class reference, what should I write for the function StartFlying? 1) StartFlying is a function of type IFly . 2) StartFlying is a function of type Airplane 3) StartFlying is a function of type Bird. My opinion is 2 and 3 are more informative. But what i see is that class references use the 1st one. They say what interface the function is declared in. Problem is, I really don't get any usable information from knowing StartFlying is IFly type. However, knowing that StartFlying is a function inside Airplane and Bird, is more informative, as I can decide which instance (Airplane or Bird ) to use. Any lights on this: how saying StartFlying is a function of type IFly, can help a programmer understanding how to use the function?

  Read the article

• determine complex type from a primitive type using reflection

  - by Nilotpal Das

  I am writing a tool where I need to reflect upon methods and if the parameters of the methods are complex type, then I need to certain type of actions such as instantiating them etc. Now I saw the IsPrimitive property in the Type variable. However, it shows string and decimal as complex types, which technically isn't incorrect. However what I really want is to be able to distinguish developer created class types from system defined data types. Is there any way that I can do this?

  Read the article

• Hot to get generic type from object type

  - by Murat

  My Classes are; class BaseClass { } class DerivedClass1 : BaseClass { } class GenericClass<T> { } class DerivedClass2 : BaseClass { GenericClass<DerivedClass1> subItem; } I want to access all fields of DerivedClass2 class. I use System.Reflection and FieldInfo.GetValue() method; Bu I cant get subItem field. FieldInfo.GetValue() method return type is "object". And I cant cast to GenericClass<DerivedClass1> or I cant get DerivedClass1 type. I try this with BaseClass BaseClass instance = FieldInfo.Getvalue(this) as GenericClass<BaseClass>; but instance is null. How to get instance with type or how to get only type?

  Read the article

• Scala type system : basic type mismatch

  - by SiM

  I have a basic type system type mismatch problem: I have a class with a method def Create(nodeItem : NodeItem) = {p_nodeStart.addEndNode(nodeItem)} where p_nodeStart is NodeCache class NodeCache[END_T<:BaseNode] private(node: Node) extends BaseNode { def addEndNode(endNode : END_T) = {this.CACHE_HAS_ENDNODES.Create(endNode)} and the error its giving me is: error: type mismatch; found : nodes.NodeItem required: Nothing def Create(nodeItem : NodeItem) = {p_nodeStart.addEndNode(nodeItem)} while the NodeCache is defined as object NodeTrigger { def Create() { val nodeTimeCache = NodeCache.Create[NodeItem](node) and in object NodeCache object NodeCache { def Create[END_T<:BaseNode]() { val nodeCache = new NodeCache[END_T](node); Any ideas, how to fix the error?

  Read the article

• A follow up on type coercion in C++, as it may be construed by type conversion

  - by David

  This is a follow up to my previous question. Consider that I write a function with the following prototype: int a_function(Foo val); Where foo is believed to be a type defined unsigned int. This is unfortunately not verifiable for lack of documentation. So, someone comes along and uses a_function, but calls it with an unsigned int as an argument. Here the story takes a turn. Foo turns out to actually be a class, which can take an unsigned int as a single argument of unsigned int in an explicit constructor. Is it a standard and reliable behavior for the compiler to render the function call by doing a type conversion on the argument. I.e. is the compiler supposed to recognize the mismatch and insert the constructor? Or should I get a compile time error reporting the type mismatch.

  Read the article

• Dynamic type languages versus static type languages

  - by cvs

  What are the advantages and limitations of dynamic type languages compared to static type languages? See also: whats with the love of dynamic languages (a far more argumentative thread...)

  Read the article

• Which statically typed languages support intersection types for function return values?

  - by stakx

  Initial note: This question got closed after several edits because I lacked the proper terminology to state accurately what I was looking for. Sam Tobin-Hochstadt then posted a comment which made me recognise exactly what that was: programming languages that support intersection types for function return values. Now that the question has been re-opened, I've decided to improve it by rewriting it in a (hopefully) more precise manner. Therefore, some answers and comments below might no longer make sense because they refer to previous edits. (Please see the question's edit history in such cases.) Are there any popular statically & strongly typed programming languages (such as Haskell, generic Java, C#, F#, etc.) that support intersection types for function return values? If so, which, and how? (If I'm honest, I would really love to see someone demonstrate a way how to express intersection types in a mainstream language such as C# or Java.) I'll give a quick example of what intersection types might look like, using some pseudocode similar to C#: interface IX { … } interface IY { … } interface IB { … } class A : IX, IY { … } class B : IX, IY, IB { … } T fn() where T : IX, IY { return … ? new A() : new B(); } That is, the function fn returns an instance of some type T, of which the caller knows only that it implements interfaces IX and IY. (That is, unlike with generics, the caller doesn't get to choose the concrete type of T — the function does. From this I would suppose that T is in fact not a universal type, but an existential type.) P.S.: I'm aware that one could simply define a interface IXY : IX, IY and change the return type of fn to IXY. However, that is not really the same thing, because often you cannot bolt on an additional interface IXY to a previously defined type A which only implements IX and IY separately. Footnote: Some resources about intersection types: Wikipedia article for "Type system" has a subsection about intersection types. Report by Benjamin C. Pierce (1991), "Programming With Intersection Types, Union Types, and Polymorphism" David P. Cunningham (2005), "Intersection types in practice", which contains a case study about the Forsythe language, which is mentioned in the Wikipedia article. A Stack Overflow question, "Union types and intersection types" which got several good answers, among them this one which gives a pseudocode example of intersection types similar to mine above.

  Read the article

• How Can I Check an Object to See its Type and Return A Casted Object

  - by Russ Bradberry

  I have method to which I pass an object. In this method I check it's type and depending on the type I do something with it and return a Long. I have tried every which way I can think of to do this and I always get several compiler errors telling me it expects a certain object but gets another. Can someone please explain to me what I am doing wrong and guide me in the right direction? What I have tried thus far is below: override def getInteger(obj:Object) = { if (obj.isInstanceOf[Object]) null else if (obj.isInstanceOf[Number]) (obj:Number).longValue() else if (obj.isInstanceOf[Boolean]) if (obj:Boolean) 1 else 0 else if (obj.isInstanceOf[String]) if ((obj:String).length == 0 | (obj:String) == "null") null else try { Long.parse(obj:String) } catch { case e: Exception => throw new ValueConverterException("value \"" + obj.toString() + "\" of type " + obj.getClass().getName() + " is not convertible to Long") } }

  Read the article

• SQL SERVER – Summary of Month – Wait Type – Day 28 of 28

  - by pinaldave

  I am glad to announce that the month of Wait Types and Queues very successful. I am glad that it was very well received and there was great amount of participation from community. I am fortunate to have some of the excellent comments throughout the series. I want to dedicate this series to all the guest blogger – Jonathan, Jacob, Glenn, and Feodor for their kindness to take a participation in this series. Here is the complete list of the blog posts in this series. I enjoyed writing the series and I plan to continue writing similar series. Please offer your opinion. SQL SERVER – Introduction to Wait Stats and Wait Types – Wait Type – Day 1 of 28 SQL SERVER – Signal Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28 SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28 SQL SERVER – DMV – sys.dm_os_waiting_tasks and sys.dm_exec_requests – Wait Type – Day 4 of 28 SQL SERVER – Capturing Wait Types and Wait Stats Information at Interval – Wait Type – Day 5 of 28 SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28 SQL SERVER – CXPACKET – Parallelism – Advanced Solution – Wait Type – Day 7 of 28 SQL SERVER – SOS_SCHEDULER_YIELD – Wait Type – Day 8 of 28 SQL SERVER – PAGEIOLATCH_DT, PAGEIOLATCH_EX, PAGEIOLATCH_KP, PAGEIOLATCH_SH, PAGEIOLATCH_UP – Wait Type – Day 9 of 28 SQL SERVER – IO_COMPLETION – Wait Type – Day 10 of 28 SQL SERVER – ASYNC_IO_COMPLETION – Wait Type – Day 11 of 28 SQL SERVER – PAGELATCH_DT, PAGELATCH_EX, PAGELATCH_KP, PAGELATCH_SH, PAGELATCH_UP – Wait Type – Day 12 of 28 SQL SERVER – FT_IFTS_SCHEDULER_IDLE_WAIT – Full Text – Wait Type – Day 13 of 28 SQL SERVER – BACKUPIO, BACKUPBUFFER – Wait Type – Day 14 of 28 SQL SERVER – LCK_M_XXX – Wait Type – Day 15 of 28 SQL SERVER – Guest Post – Jonathan Kehayias – Wait Type – Day 16 of 28 SQL SERVER – WRITELOG – Wait Type – Day 17 of 28 SQL SERVER – LOGBUFFER – Wait Type – Day 18 of 28 SQL SERVER – PREEMPTIVE and Non-PREEMPTIVE – Wait Type – Day 19 of 28 SQL SERVER – MSQL_XP – Wait Type – Day 20 of 28 SQL SERVER – Guest Posts – Feodor Georgiev – The Context of Our Database Environment – Going Beyond the Internal SQL Server Waits – Wait Type – Day 21 of 28 SQL SERVER – Guest Post – Jacob Sebastian – Filestream – Wait Types – Wait Queues – Day 22 of 28 SQL SERVER – OLEDB – Link Server – Wait Type – Day 23 of 28 SQL SERVER – 2000 – DBCC SQLPERF(waitstats) – Wait Type – Day 24 of 28 SQL SERVER – 2011 – Wait Type – Day 25 of 28 SQL SERVER – Guest Post – Glenn Berry – Wait Type – Day 26 of 28 SQL SERVER – Best Reference – Wait Type – Day 27 of 28 SQL SERVER – Summary of Month – Wait Type – Day 28 of 28 Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, SQLServer, T SQL, Technology

  Read the article

• Is type safety worth the trade-offs?

  - by Prof Plum

  I began coding in in Python primarily where there is no type safety, then moved to C# and Java where there is. I found that I could work a bit more quickly and with less headaches in Python, but then again, my C# and Java apps are at much higher level of complexity so I have never given Python a true stress test I suppose. The Java and C# camps make it sound like without the type safety in place, most people would be running into all sorts of horrible bugs left an right and it would be more trouble than its worth. This is not a language comparison, so please do not address issues like compiled vs interpreted. Is type safety worth the hit to speed of development and flexibilty? WHY? to the people who wanted an example of the opinion that dynamic typing is faster: "Use a dynamically typed language during development. It gives you faster feedback, turn-around time, and development speed." - http://blog.jayway.com/2010/04/14/static-typing-is-the-root-of-all-evil/

  Read the article

1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >