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  • iPhone static library Clang/LLVM error: non_lazy_symbol_pointers

    - by Bekenn
    After several hours of experimentation, I've managed to reduce the problem to the following example (C++): extern "C" void foo(); struct test { ~test() { } }; void doTest() { test t; // 1 foo(); // 2 } This is being compiled for iOS devices in XCode 4.2, using the provided Clang compiler (Apple LLVM compiler 3.0) and the iOS 5.0 SDK. The project is configured as a Cocoa Touch Static Library, and "Enable Linking With Shared Libraries" is set to No because I'm building an AIR native extension. The function foo is defined in another external library. (In my actual project, this would be any of the C API functions defined by Adobe for use in AIR native extensions.) When attempting to compile this code, I get back the error: FATAL:incompatible feature used: section type non_lazy_symbol_pointers (must specify "-dynamic" to be used) clang: error: assembler command failed with exit code 1 (use -v to see invocation) The error goes away if I comment out either of the lines marked 1 or 2 above, or if I change the build setting "Enable Linking With Shared Libraries" to Yes. (However, if I change the build setting, then I get multiple ld warning: unexpected srelocation type 9 warnings when linking the library into the final project, and the application crashes when running on the device.) The build error also goes away if I remove the destructor from test. So: Is this a bug in Clang? Am I missing some all-important and undocumented build setting? The interaction between an externally-provided function and a struct with a destructor is very peculiar, to say the least.

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  • Getting the name of a child class in the parent class (static context)

    - by Benoit Myard
    Hi everybody, I'm building an ORM library with reuse and simplicity in mind; everything goes fine except that I got stuck by a stupid inheritance limitation. Please consider the code below: class BaseModel { /* * Return an instance of a Model from the database. */ static public function get (/* varargs */) { // 1. Notice we want an instance of User $class = get_class(parent); // value: bool(false) $class = get_class(self); // value: bool(false) $class = get_class(); // value: string(9) "BaseModel" $class = __CLASS__; // value: string(9) "BaseModel" // 2. Query the database with id $row = get_row_from_db_as_array(func_get_args()); // 3. Return the filled instance $obj = new $class(); $obj->data = $row; return $obj; } } class User extends BaseModel { protected $table = 'users'; protected $fields = array('id', 'name'); protected $primary_keys = array('id'); } class Section extends BaseModel { // [...] } $my_user = User::get(3); $my_user->name = 'Jean'; $other_user = User::get(24); $other_user->name = 'Paul'; $my_user->save(); $other_user->save(); $my_section = Section::get('apropos'); $my_section->delete(); Obviously, this is not the behavior I was expecting (although the actual behavior also makes sense).. So my question is if you guys know of a mean to get, in the parent class, the name of child class.

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  • How can I get a static URL to a map image using the Google Static Maps API?

    - by Argote
    === BACKGROUND === Hello, so I've published a Web-App (still in "Beta") which uses the Flickr API to get information for the photos of a particular Flickr user and generates IPB code to post any of his/her images. While Flickr now gives you the IPB code to show the image and link back to the photo site directly on its site, my App also has the option of embeding the title, description, select EXIF data, location information, etc. into the post for the IPB forum. === PROBLEM === I've most recently added the option to integrate a Google Maps image of the photo's geolocation data into the post by using the Google Static Maps API. The problem is that the image URL I have is in the following form (including IPB [IMG] tags): [IMG]http://maps.google.com/maps/api/staticmap?zoom=16&size=600x600&maptype=hybrid&markers=19.387687,-99.251732&sensor=false[/IMG] Which shows this example image (In practice the image size is user selectable): However, some IPB forums seem to not support dyamic image URLs which gives me a broken image, I'd like to replace the [IMG]http://maps.google.com/maps/api/staticmap?zoom=16&size=600x600&maptype=hybrid&markers=19.387687,-99.251732&sensor=false[/IMG] with something like [IMG]http://maps.google.com/maps/api/staticmap/map0000001.png[/IMG] which should be supported by all IPB forums. Thanks in advance for your help. In case you're interested, the most recent "released" version of my Web-App can be found here: http://flickr.argote.mx/ (The changes I mention here are still on local development server).

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  • Are there any C++ tools that detect misuse of static_cast, dynamic_cast, and reinterpret_cast?

    - by chrisp451
    The answers to the following question describe the recommended usage of static_cast, dynamic_cast, and reinterpret_cast in C++: http://stackoverflow.com/questions/332030/when-should-static-cast-dynamic-cast-and-reinterpret-cast-be-used Do you know of any tools that can be used to detect misuse of these kinds of cast? Would a static analysis tool like PC-Lint or Coverity Static Analysis do this? The particular case that prompted this question was the inappropriate use of static_cast to downcast a pointer, which the compiler does not warn about. I'd like to detect this case using a tool, and not assume that developers will never make this mistake.

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  • Django choking oddly on some static media

    - by Edan Maor
    My situation: I'm serving static media via Django on my dev machine. On some files that I try and load, I get back this error: Traceback: File "c:\Program Files\Python26\Lib\site-packages\django\core\handlers\base.py" in get_response 92. response = callback(request, *callback_args, **callback_kwargs) File "E:\Stack2Blog\src.hg\stack2blog\..\stack2blog\stack2blogapp\views.py" in userpage 71. so_user = site.user(userid) File "E:\Stack2Blog\src.hg\stack2blog\..\stack2blog\stack2blogapp\stackexchange.py" in user 476. u, = self.users((nid,), **kw) File "E:\Stack2Blog\src.hg\stack2blog\..\stack2blog\stack2blogapp\stackexchange.py" in users 481. return self._get(User, ids, 'users', kw) File "E:\Stack2Blog\src.hg\stack2blog\..\stack2blog\stack2blogapp\stackexchange.py" in _get 471. return self.build(root, typ, coll, kw) File "E:\Stack2Blog\src.hg\stack2blog\..\stack2blog\stack2blogapp\stackexchange.py" in build 448. json = self._request(url, kw) File "E:\Stack2Blog\src.hg\stack2blog\..\stack2blog\stack2blogapp\stackexchange.py" in _request 422. dump = json.load(data) File "c:\Program Files\Python26\lib\json\__init__.py" in load 264. return loads(fp.read(), Exception Type: AttributeError at /userpage/362498 Exception Value: 'str' object has no attribute 'read' I've traced it to specific files which don't work (by going to their specific urls). Here's the odd part: changing the filename of the files makes them suddenly work. For example, I had a file called 'post.jpg', which gave this error. I renamed it to 'pos.jpg' and it worked. Back to 'post.jpg' and it gives the same error.

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  • Care to be taken when serving static content (JS, CSS, Media) from different domain?

    - by Aahan Krish
    Let me try to explain by example. Say website is hosted at example.com (NOT www.example.com). In order to serve static content cookie-free, I've chosen to use a different domain example-static.com. Now, lets consider that my static content is currently served like this: http://example.com/js/script.js http://example.com/css/style.css http://example.com/media/image.jpg ** Now I create a CNAME record aliasing example-static.com to my main domain i.e. example.com so that the static content is served as such: http://example-static.com/js/script.js http://example-static.com/css/style.css http://example-static.com/media/image.jpg ** Is that all I have to do? Will all browsers execute JavaScript files and load web fonts without any security concerns? OR should I be using some .htaccess rules to modify header information and the like? PS: It would be great if you can provide what rules should be added, if need be.

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  • VS2010 Code Analysis, any way to automatically fix certain warnings?

    - by JL
    I must say I really like the new code analysis with VS 2010, I have a lot of areas in my code where I am not using CultureInfo.InvariantCultureand code analysis is warming me about this. I am pretty sure I want to use CultureInfo.InvariantCulturewhere ever code analysis has detected it is missing on Convert.ToString operations. Is there anyway to get VS to automatically fix warnings of this type?

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  • Lightweight HTTP application/server for static content

    - by PartlyCloudy
    Hi, I am in need of a scalable and performant HTTP application/server that will be used for static file serving/uploading. So I only need support for GET and PUT operations. However, there are a few extra features that I need: Custom authentication: I need to check credentials against a database for each request. Thus I must be able to integrate propietary database interaction. Support for signed access keys: The access to resources via PUT should be signed using a key like http://uri/?key=foo The key then contains information about the request like md5(user + path + secret) which allows me to block unwanted requests. The application/server should allow me to check for this. Performance: I'd like to avoid piping content as much as possible. Otherwise the whole application could be implemented in Perl/etc. in a few lines as CGI. Perlbal (in webserver mode) looks nice, however the single-threaded model does not fit with my database lookup and it does also not support query strings. Lighttp/Nginx/… have some modules for these tasks, however it is not feasible putting everything together without ending up writing own extensions/modules. So how would you solve this? Are there other leightweight webservers available for this? Should I implement an application inside of a webserver (i.e. CGI). How can I avoid/speed up piping content between the webserver and my application. Thanks in advance!

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  • Static libraries in version-cross-compiled program

    - by Brian Postow
    I have a unix command line app (with big nasty makefile) that I'm trying to run on a mac. I am compiling it on a 10.6 system, with all of the appropriate libraries of course. The deployment environment is a 10.5 system, with no extra libraries. I compiled without -dynamic, and it appears to have static libraries, correctly. When I run it on the 10.6 system, it works. However, when I run it on the 10.5 system, I get: dyld: unknown required load command 0x80000022 I got this same error when I compiled things for the 10.6 system using the 10.5 xcode, so it looks like a version mis-match type problem. However, I used gcc-4.0, and $CFLAGS = -isysroot /Developer/SDKs/MacOSX10.5.sdk -mmacosx-version-min=10.5 so it SHOULD be set up for 10.5... any ideas? thanks Editing an ancient question: I have the exact same problem on a different computer. This time I am at 10.5.8, fully update, the same executable works on 10.6 still. Has anyone had any luck with this in the months since I asked this?

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  • C++ private inheritance and static members/types

    - by WearyMonkey
    I am trying to stop a class from being able to convert its 'this' pointer into a pointer of one of its interfaces. I do this by using private inheritance via a middle proxy class. The problem is that I find private inheritance makes all public static members and types of the base class inaccessible to all classes under the inheriting class in the hierarchy. class Base { public: enum Enum { value }; }; class Middle : private Base { }; class Child : public Middle { public: void Method() { Base::Enum e = Base::value; // doesn't compile BAD! Base* base = this; // doesn't compile GOOD! } }; I've tried this in both VS2008 (the required version) and VS2010, neither work. Can anyone think of a workaround? Or a different approach to stopping the conversion? Also I am curios of the behavior, is it just a side effect of the compiler implementation, or is it by design? If by design, then why? I always thought of private inheritance to mean that nobody knows Middle inherits from Base. However, the exhibited behavior implies private inheritance means a lot more than that, in-fact Child has less access to Base than any namespace not in the class hierarchy!

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  • How to use external static files with Django (serving external files once again)?

    - by Tomas Novotny
    Hi, even after Googling and reading all relevant posts at StackOverflow, I still can't get static files working in my Django application. Here is how my files look: settings.py MEDIA_ROOT = os.path.join(SITE_ROOT, 'static') MEDIA_URL = '/static/' urs.py from DjangoBandCreatorSite.settings import DEBUG if DEBUG: urlpatterns += patterns('', ( r'^static/(?P<path>.*)$', 'django.views.static.serve', {'document_root': 'static'} )) template: <script type="text/javascript" src="/static/jquery.js"></script> <script type="text/javascript"> I am trying to use jquery.js stored in directory "static". I am using: Windows XP Python 2.6.4 Django 1.2.3 Thank you very much for any help

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  • Do you recommend Enabling Code Analysis for C/C++ on Build?

    - by brickner
    I'm using Visual Studio 2010, and in my C++/CLI project there are two Code Analysis settings: Enable Code Analysis on Build Enable Code Analysis for C/C++ on Build My question is about the second setting. I've enabled it and it takes a long time to run and it doesn't find much. Do you recommend enabling this feature? Why?

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  • Delphi static method of a class returning property value

    - by mitko.berbatov
    I'm making a Delphi VCL application. There is a class TStudent where I have two static functions: one which returns last name from an array of TStudent and another one which returns the first name of the student. Their code is something like: class function TStudent.FirstNameOf(aLastName: string): string; var i : integer; begin for i := 0 to Length(studentsArray) - 1 do begin if studentsArray[i].LastName = aLastName then begin result := studentsArray[i].FirstName; Exit; end; end; result := 'no match was found'; end; class function TStudent.LastNameOf(aFirstName: string): string; var i : integer; begin for i := 0 to Length(studentsArray) - 1 do begin if studentsArray[i].FirstName = aFirstName then begin result := studentsArray[i].LastName; Exit; end; end; result := 'no match was found'; end; My question is how can I avoid writing almost same code twice. Is there any way to pass the property as parameter of the functions.

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  • Scoring/analysis of Subjective testing for skills assessment

    - by ChrisBint
    I am lucky in the sense that I have been given the opportunity to be a 'Technical Troubleshooter' for our offshore development team. While I am confident and capable of dealing with most issues, I have come across something that I am not. Based on initial discussions with various team members both on and offshore, a requirement for a 'repeatable, consistent' skills assessment has been identified. In my opinion, the best way to achieve this would be a combination of objective and subjective tests. The former normally being an initial online skills assessment on various subjects, for example General C#, WCF and MVC. The latter being a technical test where the candidate would need to solve various problems and (hopefully) explain the thought processes involved with the solution whilst doing so. Obviously, the first method is consistent, repeatable and extremely accurate. The second is always going to be subjective and based on the approach, the solution (or possibly not) and other factors. The 'scoring' of this is also going to be down to the experience and skills of the assessor and this is where my problem lies; The person that is expected to be the assessor initially (me) has no experience. The people that will ultimately continue this process for other people will never remain the same due to project constraints and internal reasons, this changes the baseline for comparison. I am not aware of any suitable system that can be classed as consistent and repeatable for subjective tests with the 2 factors above, let alone if those did not exist. So anyway, I have to present a plan that will ultimately generate a skills/gap analysis and it is unlikely that I will be able to use an objective method (budget constraints most likely reason). The only option left is the subjective methods and the issues above. Does anyone have any suggestions for an approach that may tick all the boxes?

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  • WolframAlpha Can Now Do In-depth Analysis of Your Facebook Account

    - by Jason Fitzpatrick
    If you’re a big fan of WolframAlpha’s ability to crunch the numbers on just about anything–and we certainly are–you’ll likely be just as delighted as we were to watch it massage the data from your Facebook account. Find out your most liked, discussed, and shared posts, see your Facebook habits, and other neat trends. I unleashed it on my account this morning, not sure what to expect from the results. Within the results tabulation WolframAlpha provided me with all sorts of neat data break downs. I now know exactly how many days it is to my next birthday, the composition of my aggregate posting habits (how many posts are status updates, links, or photos), the time of day when I do the most posting (and what the composition of those posts is), and my average post length. I also know my most liked post and my most commented on post. It will even crunch the numbers on your network of friends (60.6% of my friends are married, for example). By far one of the more interesting data analysis it does on the friendship data, however, is organizing all your friends into relationship clusters so you can see who in your Facebook network is friends with other people in your Facebook network. The service from WolframAlpha is free: simply visit the WolframAlpha search portal and type in “Facebook report” to start the process. You’ll be prompted to create a WolframAlpha account if you don’t have one and to authorize the WolframAlpha Facebook app to access your data. Your Facebook data is cached to your WolframAlpha account for one hour in order to crunch the numbers and display the results. WolframAlpha HTG Explains: How Windows Uses The Task Scheduler for System Tasks HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows? Java is Insecure and Awful, It’s Time to Disable It, and Here’s How

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  • OpenCV compliation on linux: how to feed to it specific zlib lib?

    - by myWallJSON
    I want to compile OpenCV with same zlib as I use for compilation of Boost Iostreams (not system default one). I want to compile OpenCV as static lib, having zlib compiled as static lib. Currently I use something like : ../$CMAKE_PATH -DCMAKE_INSTALL_PREFIX=./$OPENCV_INSTALL_SUBDIR -DBUILD_WITH_STATIC_CRT=ON -DBUILD_SHARED_LIBS=OFF -DBUILD_PYTHON_SUPPORT=OFF -DOPENCV_EXTRA_C_FLAGS=-fPIC -DOPENCV_BUILD_3RDPARTY_LIBS=TRUE make make install echo Done! I wonder: having some $ZLIB_HEADERS and $ZLIB_LIB_FILES_FOLDER path strings how to feed them into cmake to get OpenCV compiled with built by me zlib?

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  • Software Architecture Analysis Method (SAAM)

    Software Architecture Analysis Method (SAAM) is a methodology used to determine how specific application quality attributes were achieved and how possible changes in the future will affect quality attributes based on hypothetical cases studies. Common quality attributes that can be utilized by this methodology include modifiability, robustness, portability, and extensibility. Quality Attribute: Application Modifiability The Modifiability quality attribute refers to how easy it changing the system in the future will be. This to me is a very open-ended attribute because a business could decide to transform a Point of Sale (POS) system in to a Lead Tracking system overnight. (Yes, this did actually happen to me) In order for SAAM to be properly applied for checking this attribute specific hypothetical case studies need to be created and review for the modifiability attribute due to the fact that various scenarios would return various results based on the amount of changes. In the case of the POS change out a payment gateway or adding an additional payment would have scored very high in comparison to changing the system over to a lead management system. I personally would evaluate this quality attribute based on the S.O.I.L.D Principles of software design. I have found from my experience the use of S.O.I.L.D in software design allows for the adoption of changes within a system. Quality Attribute: Application Robustness The Robustness quality attribute refers to how an application handles the unexpected. The unexpected can be defined but is not limited to anything not anticipated in the originating design of the system. For example: Bad Data, Limited to no network connectivity, invalid permissions, or any unexpected application exceptions. I would personally evaluate this quality attribute based on how the system handled the exceptions. Robustness Considerations Did the system stop or did it handle the unexpected error? Did the system log the unexpected error for future debugging? What message did the user receive about the error? Quality Attribute: Application Portability The Portability quality attribute refers to the ease of porting an application to run in a new operating system or device. For example, It is much easier to alter an ASP.net website to be accessible by a PC, Mac, IPhone, Android Phone, Mini PC, or Table in comparison to desktop application written in VB.net because a lot more work would be involved to get the desktop app to the point where it would be viable to port the application over to the various environments and devices. I would personally evaluate this quality attribute based on each new environment for which the hypothetical case study identifies. I would pay particular attention to the following items. Portability Considerations Hardware Dependencies Operating System Dependencies Data Source Dependencies Network Dependencies and Availabilities  Quality Attribute: Application Extensibility The Extensibility quality attribute refers to the ease of adding new features to an existing application without impacting existing functionality. I would personally evaluate this quality attribute based on each new environment for the following Extensibility  Considerations Hard coded Variables versus Configurable variables Application Documentation (External Documents and Codebase Documentation.) The use of Solid Design Principles

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  • Deadlock Analysis in NetBeans 8

    - by Geertjan
    Lock contention profiling is very important in multi-core environments. Lock contention occurs when a thread tries to acquire a lock while another thread is holding it, forcing it to wait. Lock contentions result in deadlocks. Multi-core environments have even more threads to deal with, causing an increased likelihood of lock contentions. In NetBeans 8, the NetBeans Profiler has new support for displaying detailed information about lock contention, i.e., the relationship between the threads that are locked. After all, whenever there's a deadlock, in any aspect of interaction, e.g., a political deadlock, it helps to be able to point to the responsible party or, at least, the order in which events happened resulting in the deadlock. As an example, let's take the handy Deadlock sample code from the Java Tutorial and look at the tools in NetBeans IDE for identifying and analyzing the code. The description of the deadlock is nice: Alphonse and Gaston are friends, and great believers in courtesy. A strict rule of courtesy is that when you bow to a friend, you must remain bowed until your friend has a chance to return the bow. Unfortunately, this rule does not account for the possibility that two friends might bow to each other at the same time. To help identify who bowed first or, at least, the order in which bowing took place, right-click the file and choose "Profile File". In the Profile Task Manager, make the choices below: When you have clicked Run, the Threads window shows the two threads are blocked, i.e., the red "Monitor" lines tell you that the related threads are blocked while trying to enter a synchronized method or block: But which thread is holding the lock? Which one is blocked by the other? The above visualization does not answer these questions. New in NetBeans 8 is that you can analyze the deadlock in the new Lock Contention window to determine which of the threads is responsible for the lock: Here is the code that simulates the lock, very slightly tweaked at the end, where I use "setName" on the threads, so that it's even easier to analyze the threads in the relevant NetBeans tools. Also, I converted the anonymous inner Runnables to lambda expressions. package org.demo; public class Deadlock { static class Friend { private final String name; public Friend(String name) { this.name = name; } public String getName() { return this.name; } public synchronized void bow(Friend bower) { System.out.format("%s: %s" + " has bowed to me!%n", this.name, bower.getName()); bower.bowBack(this); } public synchronized void bowBack(Friend bower) { System.out.format("%s: %s" + " has bowed back to me!%n", this.name, bower.getName()); } } public static void main(String[] args) { final Friend alphonse = new Friend("Alphonse"); final Friend gaston = new Friend("Gaston"); Thread t1 = new Thread(() -> { alphonse.bow(gaston); }); t1.setName("Alphonse bows to Gaston"); t1.start(); Thread t2 = new Thread(() -> { gaston.bow(alphonse); }); t2.setName("Gaston bows to Alphonse"); t2.start(); } } In the above code, it's extremely likely that both threads will block when they attempt to invoke bowBack. Neither block will ever end, because each thread is waiting for the other to exit bow. Note: As you can see, it really helps to use "Thread.setName", everywhere, wherever you're creating a Thread in your code, since the tools in the IDE become a lot more meaningful when you've defined the name of the thread because otherwise the Profiler will be forced to use thread names like "thread-5" and "thread-6", i.e., based on the order of the threads, which is kind of meaningless. (Normally, except in a simple demo scenario like the above, you're not starting the threads in the same class, so you have no idea at all what "thread-5" and "thread-6" mean because you don't know the order in which the threads were started.) Slightly more compact: Thread t1 = new Thread(() -> { alphonse.bow(gaston); },"Alphonse bows to Gaston"); t1.start(); Thread t2 = new Thread(() -> { gaston.bow(alphonse); },"Gaston bows to Alphonse"); t2.start();

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  • configure.in: AM_DISABLE_SHARED doesn't change my Makefile

    - by t2k32316
    I'm extremely new to using Makefiles and autoconf. I'm using the Camellia image library and trying to statically link my code against their libraries. When I run "make" on the Camellia image library, I get libCamellia.a, .so, .la, and .so.0.0.0 files inside my /usr/local/lib directory. This is the command I use to compile my code with their libraries: gcc -L/usr/local/lib -lCamellia -o myprogram myprogram.c This works fine, but when I try to statically link, this is what I get: gcc -static -L/usr/local/lib -lCamellia -o myprogram myprogram.c /tmp/cck0pw70.o: In function `main': myprogram.c:(.text+0x23): undefined reference to `camLoadPGM' myprogram.c:(.text+0x55): undefined reference to `camAllocateImage' myprogram.c:(.text+0x97): undefined reference to `camZoom2x' myprogram.c:(.text+0x104): undefined reference to `camSavePGM' collect2: ld returned 1 exit status I want to statically link because I'm trying to modify the Camellia source code and I want to compare my version against theirs. So after some googling, I tried adding AM_DISABLE_SHARED into the configure.in file. But after running ./configure, I still get the exact same Makefile. After I "make install", I still get the same results above. What is an easy way to get two versions of my code, one with the original Camellia source code compiled and one with my modified version? I think static libraries should work. There is an easy way to get static libraries working or are there other simple solutions to my problem? I just don't want to re-"make" and re-"make install" everytime I want to compare my version against the original.

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  • Static lib that links another static lib and qmake? Odd linking error

    - by Dan O
    I have two qt .pro files, both using the lib TEMPLATE and staticlib CONFIG. The first library (lets call it 'core') is a dependency for the second lib (I'll call it 'foo'). In fact, there's a class in foo that extends a class in core, I will call this class Bar. When I instantiate the class (which is defined and implemented in foo, but extends a class (Bar) from core) in another project (not a lib) I get the following linking error: /usr/bin/ld: Undefined symbols: Bar::Bar() Basically, the linker cannot find the class in the core lib that has been derived in the foo lib, but ONLY when I instantiate the class in a third project that is using both libs. Is this behaviour expected? Regards, Dan O Update: I fixed it by directly invoking the Bars constructor in the third project before using derived class... does anyone know why I need to do this?

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  • static arrays defined with unspecified size, empty brackets?

    - by ahmadabdolkader
    For the C++ code fragment below: class Foo { int a[]; // no error }; int a[]; // error: storage size of 'a' isn't known void bar() { int a[]; // error: storage size of 'a' isn't known } why isn't the member variable causing an error too? and what is the meaning of this member variable? I'm using gcc version 3.4.5 (mingw-vista special) through CodeBlocks 8.02. On Visual Studio Express 2008 - Microsoft(R) C/C++ Optimizing Compiler 15.00.30729.01 for 80x86, I got the following messages: class Foo { int a[]; // warning C4200: nonstandard extension used : zero-sized array in struct/union - Cannot generate copy-ctor or copy-assignment operator when UDT contains a zero-sized array }; int a[]; void bar() { int a[]; // error C2133: 'a' : unknown size } Now, this needs some explaination too.

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  • Static classes in PHP via abstract keyword?

    - by Boldewyn
    According to the PHP manual, a class like this: abstract class Example {} cannot be instantiated. If I need a class without instance, e.g. for a registry pattern: class Registry {} // and later: echo Registry::$someValue; would it be considered good style to simply declare the class as abstract? If not, what are the advantages of hiding the constructor as protected method compared to an abstract class? Rationale for asking: As far as I see it, it could a bit of feature abuse, since the manual refers to abstract classes more as like blueprints for later classes with instantiation possibility.

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  • Access static class variable of parent class in Python

    - by fuenfundachtzig
    I have someting like this class A: __a = 0 def __init__(self): A.__a = A.__a + 1 def a(self): return A.__a class B(A): def __init__(self): # how can I access / modify A.__a here? A.__a = A.__a + 1 # does not work def a(self): return A.__a Can I access the __astatic variable in B? It's possible writing a instead of __a, is this the only way? (I guess the answer might be rather short: yes :)

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