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• Force windows video driver reload. Is it possible at all?

  - by somemorebytes

  Hi there, Some drivers use parameters written in the registry to configure themselves when they get loaded at boot time. I can modify those values and then reboot, but I would like to know if it is possible to force the driver reload, making the changes effective without rebooting. Specifically, I am talking about the video driver (nvidia). I read somewhere, that calling through pINvoke() [User32.ll]::ChangeDisplaySettings() with a 640x480x8bits resolution,(which is so low that it should not be supported by a modern driver) will force windows to load the "Standard VGA driver", and making another call with the current resolution will load the nvidia driver again. This does not work though. At least in Windows 7, even if the low res is not displayed as "supported" the system reduces the screen to a little square in the center of the screen, showing the low res wihtout unloading the nvidia driver. So, is there any .NET/Win32 API, service to restart, or any way at all to force a video driver reload? Perhaps programatically disabling the device (as you could do from the Device Manager) and reenabling it again? Any idea? Thanks a lot.

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• C++: Efficiently adding integers to strings

  - by Shinka

  I know how to add integers to strings, but I'm not sure I'm doing it in an efficient matters. I have a class where I often have to return a string plus an integer (a different integer each time), in Java I would do something like public class MyClass { final static String S = "MYSTRING"; private int id = 0; public String getString() { return S + (id++); } } But in C++ I have to do; class MyClass { private: std::string S; // For some reason I can't do const std::string S = "MYSTRING"; int id; public: MyClass() { S = "MYSTRING"; id = 0; } std::string getString() { std::ostringstream oss; oss << S << id++; return oss.str(); } } An additional constraint: I don't want (in fact, in can't) use Boost or any other librairies, I'll have to work with the standard library. So the thing is; the code works, but in C++ I have to create a bunch of ostringstream objects, so it seems inefficient. To be fair, perhaps Java do the same and I just don't notice it, I say it's inefficient mostly because I know very little about strings. Is there a more efficient way to do this ?

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• increase number of photos from flickr using json

  - by Andrew Welch

  Hi this is my code: Is is possible to get more photos from flickr. What is the standard / default number? $(document).ready(function(){ $.getJSON("http://api.flickr.com/services/feeds/photos_public.gne?id=48719970@N07&lang=en-us&format=json&jsoncallback=?", function(data){ $.each(data.items, function(i, item){ var newurl = 'url(' + item.media.m + ')'; $("<div class='images'/>").css('background', newurl).css('backgroundPosition','top center').css('backgroundRepeat','no-repeat').appendTo("#images").wrap("<a target=\"_blank\ href='" + item.link + "'></a>"); }) $("#title").html(data.title); $("#description").html(data.description); $("#link").html("<a href='" + data.link + "' target=\"_blank\">Visit the Viget Inspiration Pool!</a>"); //Notice that the object here is "data" because that information sits outside of "items" in the JSON feed $('.jcycleimagecarousel').cycle({ fx: 'fade', speed: 300, timeout: 3000, next: '#next', prev: '#prev', pause: 1, random: 1 }); }); });

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• Boost's "cstdint" Usage

  - by patt0h

  Boost's C99 stdint implementation is awfully handy. One thing bugs me, though. They dump all of their typedefs into the boost namespace. This leaves me with three choices when using this facility: Use "using namespace boost" Use "using boost::[u]<type><width>_t" Explicitly refer to the target type with the boost:: prefix; e.g., boost::uint32_t foo = 0; Option ? 1 kind of defeats the point of namespaces. Even if used within local scope (e.g., within a function), things like function arguments still have to be prefixed like option ? 3. Option ? 2 is better, but there are a bunch of these types, so it can get noisy. Option ? 3 adds an extreme level of noise; the boost:: prefix is often = to the length of the type in question. My question is: What would be the most elegant way to bring all of these types into the global namespace? Should I just write a wrapper around boost/cstdint.hpp that utilizes option ? 2 and be done with it? Also, wrapping the header like so didn't work on VC++ 10 (problems with standard library headers): namespace Foo { #include <boost/cstdint.hpp> using namespace boost; } using namespace Foo; Even if it did work, I guess it would cause ambiguity problems with the ::boost namespace.

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• Use date operations on a computed field filter in a view

  - by stephenhay

  I'd like to expose a filter in Views based on a Computed Field. This field should utilize the date operation "less than". Apparently, a date type is not available to computed field (varchar is). However, using varchar results in views treating the field as a string rather than as a date, without the operation I'm looking for. So I tried using a timestamp instead of a date, which allowed me to use an integer data type. The exposed view gives me a "less than" operation, but as it's still not a date, the user must type in a timestamp. Not handy. So I'm thinking the best way to do this is to create a new (hidden) CCK field which is a date field, and set the value of this field to the value of the Computed Field. I can then use the new CCK field for my exposed filter. But I'm not getting anywhere with this, as I'm unsure how to set another CCK field with a Computed Field. To return the value to the computed field itself, I'm using the standard: $node_field[0]['value'] = $newestdate; I would like to set the value of the new CCK field to $newestdate as well. Can anyone help?

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• C callback functions defined in an unnamed namespace?

  - by Johannes Schaub - litb

  Hi all. I have a C++ project that uses a C bison parser. The C parser uses a struct of function pointers to call functions that create proper AST nodes when productions are reduced by bison: typedef void Node; struct Actions { Node *(*newIntLit)(int val); Node *(*newAsgnExpr)(Node *left, Node *right); /* ... */ }; Now, in the C++ part of the project, i fill those pointers class AstNode { /* ... */ }; class IntLit : public AstNode { /* ... */ }; extern "C" { Node *newIntLit(int val) { return (Node*)new IntLit(val); } /* ... */ } Actions createActions() { Actions a; a.newIntLit = &newIntLit; /* ... */ return a; } Now the only reason i put them within extern "C" is because i want them to have C calling conventions. But optimally, i would like their names still be mangled. They are never called by-name from C code, so name mangling isn't an issue. Having them mangled will avoid name conflicts, since some actions are called like error, and the C++ callback function has ugly names like the following just to avoid name clashes with other modules. extern "C" { void uglyNameError(char const *str) { /* ... */ } /* ... */ } a.error = &uglyNameError; I wondered whether it could be possible by merely giving the function type C linkage extern "C" void fty(char const *str); namespace { fty error; /* Declared! But i can i define it with that type!? */ } Any ideas? I'm looking for Standard-C++ solutions.

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• Qt application crashing immediately without debugging info. How do I track down the problem?

  - by jjacksonRIAB

  I run an Qt app I've built: ./App Segmentation fault I run it with strace: strace ./App execve("./App", ["./App"], [/* 27 vars */]) = 0 --- SIGSEGV (Segmentation fault) @ 0 (0) --- +++ killed by SIGSEGV +++ Process 868 detached Again, no useful info. I run it with gdb: (gdb) run Starting program: /root/test/App Reading symbols from shared object read from target memory...(no debugging symbols found)...done. Loaded system supplied DSO at 0xffffe000 Program received signal SIGSEGV, Segmentation fault. 0x00000001 in ?? () Again, nothing. I run it with valgrind: ==948== Process terminating with default action of signal 11 (SIGSEGV) ==948== Bad permissions for mapped region at address 0x0 ==948== at 0x1: (within /root/test/App) Even if I put in debugging symbols, it doesn't give any more useful info. ldd shows all libraries being linked properly. Is there any other way I can find out what's wrong? I can't even do standard printf, cout, etc debugging. The executable doesn't even seem to start running at all. I rebuilt with symbols, and tried the suggestion below (gdb) break main Breakpoint 1 at 0x45470 (gdb) run Starting program: /root/test/App Breakpoint 1 at 0x80045470 Reading symbols from shared object read from target memory...done. Loaded system supplied DSO at 0xffffe000 Program received signal SIGSEGV, Segmentation fault. 0x00000001 in ?? () I checked for static initializers and I don't seem to have any. Yep, I tried printf, cout, etc. It doesn't even make it into the main routine, so I'm looking for problems with static initializers in link libraries, adding them in one-by-one. I'm not getting any stack traces either.

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• LoadError in Ruby

  - by wilhelmtell

  I'm having issues requiring 'digest/sha1'. ~$ ./configure --prefix=$HOME/usr --program-suffix=19 --enable-shared ~$ make ~$ make install ~$ irb19 irb(main):001:0> require 'digest/sha1' LoadError: dlopen(/Users/matan/usr/lib/ruby19/1.9.1/i386-darwin9.8.0/digest/sha1.bundle, 9): Symbol not found: _rb_Digest_SHA1_Finish Referenced from: /Users/matan/usr/lib/ruby19/1.9.1/i386-darwin9.8.0/digest/sha1.bundle Expected in: flat namespace - /Users/matan/usr/lib/ruby19/1.9.1/i386-darwin9.8.0/digest/sha1.bundle from (irb):1:in `require' from (irb):1 from /Users/matan/usr/bin/irb19:12:in `<main>' irb(main):002:0> I know some standard modules require fine, while others don't. If i'd say require 'yaml' or even require 'digest' then that works fine. I am using OS X 10.5.8, with Ruby 1.9.1-p378. The system-wide install of Ruby 1.8.6 works fine. Just last week I uninstalled Ruby and re-installed it. When I first installed Ruby I installed it in a similar manner, from source prefixed at my local $HOME/usr directory. I tried removing each and every file make install installs, then re-installing, but that didn't help. Do you have an idea what the issue is and how to resolve it?

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• Asp.Net MVC - Binding of parameter to model value!

  - by Pino

  This seems like the model binding is causing me issues. Essentially I have a model called ProductOption and for the purpose of this question it has 2 fields ID (Int) PK ProductID (Int) FK I have a standard route set-up context.MapRoute( "Product_default", "Product/{controller}/{action}/{id}", new { controller = "Product", action = "Index", id = UrlParameter.Optional } ); and if the user wants to add an option the URL is, /Product/Options/Add/1 in the above URL 1 is the ProductID, I have the following code to return a blank model the the view, [HttpGet] public ActionResult Add(int id) { return View("Manage", new ProductOptionModel() { ProductID = id }); } Now in my view I keep a hidden field <%= Html.HiddenFor(x=>x.ID) %> This is used to determine (on submit) if we are editing or adding a new option. However the Model binder in .net seems to replace .ID (Which was 0 when leaving the above get actionresult) with 1 (or the value of the id parameter in the URL) How can I stop or work around this? ViewModel public class ProductExtraModel { //Database public int ID { get; set; } public string Name { get; set; } public int ProductID { get; set; } public ProductModel Product { get; set; } }

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• Memory leaks while using array of double

  - by Gacek

  I have a part of code that operates on large arrays of double (containing about 6000 elements at least) and executes several hundred times (usually 800) . When I use standard loop, like that: double[] singleRow = new double[6000]; int maxI = 800; for(int i=0; i<maxI; i++) { singleRow = someObject.producesOutput(); //... // do something with singleRow // ... } The memory usage rises for about 40MB (from 40MB at the beggining of the loop, to the 80MB at the end). When I force to use the garbage collector to execute at every iteration, the memory usage stays at the level of 40MB (the rise is unsignificant). double[] singleRow = new double[6000]; int maxI = 800; for(int i=0; i<maxI; i++) { singleRow = someObject.producesOutput(); //... // do something with singleRow // ... GC.Collect() } But the execution time is 3 times longer! (it is crucial) How can I force the C# to use the same area of memory instead of allocating new ones? Note: I have the access to the code of someObject class, so if it would be needed, I can change it.

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• Formulae for U and V buffer offset

  - by Abhi

  Hi all ! What should be the buffer offset value for U & V in YUV444 format type? Like for an example if i am using YV12 format the value is as follows: ppData.inputIDMAChannel.UBufOffset = iInputHeight * iInputWidth + (iInputHeight * iInputWidth)/4; ppData.inputIDMAChannel.VBufOffset = iInputHeight * iInputWidth; iInputHeight = 160 & iInputWidth = 112 ppdata is an object for the following structure: typedef struct ppConfigDataStruct { //--------------------------------------------------------------- // General controls //--------------------------------------------------------------- UINT8 IntType; // FIRSTMODULE_INTERRUPT: the interrupt will be // rised once the first sub-module finished its job. // FRAME_INTERRUPT: the interrput will be rised // after all sub-modules finished their jobs. //--------------------------------------------------------------- // Format controls //--------------------------------------------------------------- // For input idmaChannel inputIDMAChannel; BOOL bCombineEnable; idmaChannel inputcombIDMAChannel; UINT8 inputcombAlpha; UINT32 inputcombColorkey; icAlphaType alphaType; // For output idmaChannel outputIDMAChannel; CSCEQUATION CSCEquation; // Selects R2Y or Y2R CSC Equation icCSCCoeffs CSCCoeffs; // Selects R2Y or Y2R CSC Equation icFlipRot FlipRot; // Flip/Rotate controls for VF BOOL allowNopPP; // flag to indicate we need a NOP PP processing }*pPpConfigData, ppConfigData; and idmaChannel structure is as follows: typedef struct idmaChannelStruct { icFormat FrameFormat; // YUV or RGB icFrameSize FrameSize; // frame size UINT32 LineStride;// stride in bytes icPixelFormat PixelFormat;// Input frame RGB format, set NULL // to use standard settings. icDataWidth DataWidth;// Bits per pixel for RGB format UINT32 UBufOffset;// offset of U buffer from Y buffer start address // ignored if non-planar image format UINT32 VBufOffset;// offset of U buffer from Y buffer start address // ignored if non-planar image format } idmaChannel, *pIdmaChannel; I want the formulae for ppData.inputIDMAChannel.UBufOffset & ppData.inputIDMAChannel.VBufOffset for YUV444 Thanks in advance

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• What are the arguments against the inclusion of server side scripting in JavaScript code blocks?

  - by James Wiseman

  I've been arguing for some time against embedding server-side tags in JavaScript code, but was put on the spot today by a developer who seemed unconvinced The code in question was a legacy ASP application, although this is largely unimportant as it could equally apply to ASP.NET or PHP (for example). The example in question revolved around the use of a constant that they had defined in ServerSide code. 'VB Const MY_CONST: MY_CONST = 1 If sMyVbVar = MY_CONST Then 'Do Something End If //JavaScript if (sMyJsVar === "<%= MY_CONST%>"){ //DoSomething } My standard arguments against this are: Script injection: The server-side tag could include code that can break the JavaScript code Unit testing. Harder to isolate units of code for testing Code Separation : We should keep web page technologies apart as much as possible. The reason for doing this was so that the developer did not have to define the constant in two places. They reasoned that as it was a value that they controlled, that it wasn't subject to script injection. This reduced my justification for (1) to "We're trying to keep the standards simple, and defining exception cases would confuse people" The unit testing and code separation arguments did not hold water either, as the page itself was a horrible amalgam of HTML, JavaScript, ASP.NET, CSS, XML....you name it, it was there. No code that was every going to be included in this page could possibly be unit tested. So I found myself feeling like a bit of a pedant insisting that the code was changed, given the circumstances. Are there any further arguments that might support my reasoning, or am I, in fact being a bit pedantic in this insistence?

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• Connecting to SQL Server 2005 via Web Service

  - by clear-cycle-corp

  Delphi 2010, dbExpress, and SQL Server 2005 DB I am trying to make a connection to a SQL Server 2005 DB using Delphi 2010 & DBExpress. If I create a standard delphi application and hard code my connection (IT WORKS!): procedure TForm1.Button1Click(Sender: TObject); var Conn: TSQLConnection; begin Conn:= TSQLConnection.Create(nil); Conn.ConnectionName:= 'VPUCDS_VPN_SE01'; Conn.LoadParamsOnConnect := True; Conn.LoginPrompt:=True; try Conn.Connected:= True; if Conn.Connected then ShowMessage('Connected!') else ShowMessage('NOT Connected!') finally Conn.Free; end; end; All the ini files, and DLLs reside in the same folder as my executable and yes, I have DBXMsSQL & MidasLib in the uses clause again, it works if its not a web service! However, if i then move the code over to a Web services CGI module: function TTest.ConnectToDB: Boolean;stdcall; var Conn: TSQLConnection; begin Conn:= TSQLConnection.Create(nil); Conn.ConnectionName:= 'VPUCDS_VPN_SE01'; Conn.LoadParamsOnConnect := True; Conn.LoginPrompt:=True; try Conn.Connected:= True; result:= Conn.Connected; finally Conn.Free; end; end; Thanks

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• Can't get jQuery to wokr with Prototype - tried everything....

  - by thinkfuture

  Ok so here is the situation. Been pulling my hair out on this one. I'm a noob at this. Only been using rails for about 6 weeks. I'm using the standard setup package, and my code leverages prototype helpers heavily. Like I said, noob ;) So I'm trying to put in some jQuery effects, like PrettyPhoto. But what happens is that when the page is first loaded, PrettyPhoto works great. However, once someone uses a Prototype helper, like a link created with link_to_remote, Prettyphoto stops working. I've tried jRails, all of the fixes proposed on the JQuery site to stop conflicts... http://docs.jquery.com/Using_jQuery_with_Other_Libraries ...even done some crazy things likes renaming all of the $ in prototype.js to $$$ to no avail. Either the prototype helpers break, or jQuery breaks. Seems nothing I do can get these to work together. Any ideas? Here is part of my application.html.erb <%= javascript_include_tag 'application' %> <%= javascript_include_tag 'tooltip' %> <%= javascript_include_tag 'jquery' %> <%= javascript_include_tag 'jquery-ui' %> <%= javascript_include_tag "jquery.prettyPhoto" %> <%= javascript_include_tag 'prototype' %> <%= javascript_include_tag 'scriptalicious' %> </head> <body> <script type="text/javascript" charset="utf-8"> jQuery(document).ready( function() { jQuery("a[rel^='prettyPhoto']").prettyPhoto(); }); </script> If I put prototype before jquery, the prototype helpers don't work If I put the noconflict clause in, neither works. Thanks in advance! Chris

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• Reading strings and integers from .txt file and printing output as strings only

  - by screename71

  Hello, I'm new to C++, and I'm trying to write a short C++ program that reads lines of text from a file, with each line containing one integer key and one alphanumeric string value (no embedded whitespace). The number of lines is not known in advance, (i.e., keep reading lines until end of file is reached). The program needs to use the 'std::map' data structure to store integers and strings read from input (and to associate integers with strings). The program then needs to output string values (but not integer values) to standard output, 1 per line, sorted by integer key values (smallest to largest). So, for example, suppose I have a text file called "data.txt" which contains the following three lines: 10 dog -50 horse 0 cat -12 zebra 14 walrus The output should then be: horse zebra cat dog walrus I've pasted below the progress I've made so far on my C++ program: #include <fstream> #include <iostream> #include <map> using namespace std; using std::map; int main () { string name; signed int value; ifstream myfile ("data.txt"); while (! myfile.eof() ) { getline(myfile,name,'\n'); myfile >> value >> name; cout << name << endl; } return 0; myfile.close(); } Unfortunately, this produces the following incorrect output: horse cat zebra walrus If anyone has any tips, hints, suggestions, etc. on changes and revisions I need to make to the program to get it to work as needed, can you please let me know? Thanks!

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• Constructor Overloading

  - by Mark Baker

  Normally when I want to create a class constructor that accepts different types of parameters, I'll use a kludgy overloading principle of not defining any args in the constructor definition: e.g. for an ECEF coordinate class constructor, I want it to accept either $x, $y and $z arguments, or to accept a single array argument containg x, y and z values, or to accept a single LatLong object I'd create a constructor looking something like: function __construct() { // Identify if any arguments have been passed to the constructor if (func_num_args() > 0) { $args = func_get_args(); // Identify the overload constructor required, based on the datatype of the first argument $argType = gettype($args[0]); switch($argType) { case 'array' : // Array of Cartesian co-ordinate values $overloadConstructor = 'setCoordinatesFromArray'; break; case 'object' : // A LatLong object that needs converting to Cartesian co-ordinate values $overloadConstructor = 'setCoordinatesFromLatLong'; break; default : // Individual Cartesian co-ordinate values $overloadConstructor = 'setCoordinatesFromXYZ'; break; } // Call the appropriate overload constructor call_user_func_array(array($this,$overloadConstructor),$args); } } // function __construct() I'm looking at an alternative: to provide a straight constructor with $x, $y and $z as defined arguments, and to provide static methods of createECEFfromArray() and createECEFfromLatLong() that handle all the necessary extraction of x, y and z; then create a new ECEF object using the standard constructor, and return that Which option is cleaner from an OO purists perspective?

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• MySQL Stored Procedures : Use a variable as the database name in a cursor declaration

  - by Justin

  I need to use a variable to indicate what database to query in the declaration of a cursor. Here is a short snippet of the code : CREATE PROCEDURE `update_cdrs_lnp_data`(IN dbName VARCHAR(25), OUT returnCode SMALLINT) cdr_records:BEGIN DECLARE cdr_record_cursor CURSOR FOR SELECT cdrs_id, called, calling FROM dbName.cdrs WHERE lrn_checked = 'N'; # Setup logging DECLARE EXIT HANDLER FOR SQLEXCEPTION BEGIN #call log_debug('Got exception in update_cdrs_lnp_data'); SET returnCode = -1; END; As you can see, I'm TRYING to use the variable dbName to indicate in which database the query should occur within. However, MySQL will NOT allow that. I also tried things such as : CREATE PROCEDURE `update_cdrs_lnp_data`(IN dbName VARCHAR(25), OUT returnCode SMALLINT) cdr_records:BEGIN DECLARE cdr_record_cursor CURSOR FOR SET @query = CONCAT("SELECT cdrs_id, called, calling FROM " ,dbName, ".cdrs WHERE lrn_checked = 'N' "); PREPARE STMT FROM @query; EXECUTE STMT; # Setup logging DECLARE EXIT HANDLER FOR SQLEXCEPTION BEGIN #call log_debug('Got exception in update_cdrs_lnp_data'); SET returnCode = -1; END; Of course this doesn't work either as MySQL only allows a standard SQL statement in the cursor declaration. Can anyone think of a way to use the same stored procedure in multiple databases by passing in the name of the db that should be affected?

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• strcmp() but with 0-9 AFTER A-Z? (C/C++)

  - by Aaron

  For reasons I completely disagree with but "The Powers (of Anti-Usability) That Be" continue to decree despite my objections, I have a sorting routine which does basic strcmp() compares to sort by its name. It works great; it's hard to get that one wrong. However, at the 11th hour, it's been decided that entries which begin with a number should come AFTER entries which begin with a letter, contrary to the ASCII ordering. They cite the EBCDIC standard has numbers following letters so the prior assumption isn't a universal truth, and I have no power to win this argument... but I digress. Therein lies my problem. I've replaced all appropriate references to strcmp with a new function call nonstd_strcmp, and now need to implement the modifications to accomplish the sort change. I've used a FreeBSD source as my base: http://freebsd.active-venture.com/FreeBSD-srctree/newsrc/libkern/strncmp.c.html if (n == 0) return (0); do { if (*s1 != *s2++) return (*(const unsigned char *)s1 - *(const unsigned char *)(s2 - 1)); if (*s1++ == 0) break; } while (--n != 0); return (0); I guess I might need to take some time away to really think about how it should be done, but I'm sure I'm not the only one who's experienced the brain-deadness of just-before-release spec changes.

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• how does Cocoa compare to Microsoft, Qt?

  - by Paperflyer

  I have done a few months of development with Qt (built GUI programatically only) and am now starting to work with Cocoa. I have to say, I love Cocoa. A lot of the things that seemed hard in Qt are easy with Cocoa. Obj-C seems to be far less complex than C++. This is probably just me, so: Ho do you feel about this? How does Cocoa compare to WPF (is that the right framework?) to Qt? How does Obj-C compare to C# to C++? How does XCode/Interface Builder compare to Visual Studio to Qt Creator? How do the Documentations compare? For example, I find Cocoa's Outlets/Actions far more useful than Qt's Signals and Slots because they actually seem to cover most GUI interactions while I had to work around Signals/Slots half the time. (Did I just use them wrong?) Also, the standard templates of XCode give me copy/paste, undo/redo, save/open and a lot of other stuff practically for free while these were rather complex tasks in Qt. Please only answer if you have actual knowledge of at least two of these development environments/frameworks/languages.

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• Performance of C# method polymorphism with generics

  - by zildjohn01

  I noticed in C#, unlike C++, you can combine virtual and generic methods. For example: using System.Diagnostics; class Base { public virtual void Concrete() {Debug.WriteLine("base concrete");} public virtual void Generic<T>() {Debug.WriteLine("base generic");} } class Derived : Base { public override void Concrete() {Debug.WriteLine("derived concrete");} public override void Generic<T>() {Debug.WriteLine("derived generic");} } class App { static void Main() { Base x = new Derived(); x.Concrete(); x.Generic<PerformanceCounter>(); } } Given that any number of versions of Generic<T> could be instantiated, it doesn't look like the standard vtbl approach could be used to resolve method calls, and in fact it's not. Here's the generated code: x.Concrete(); mov ecx,dword ptr [ebp-8] mov eax,dword ptr [ecx] call dword ptr [eax+38h] x.Generic<PerformanceCounter>(); push 989A38h mov ecx,dword ptr [ebp-8] mov edx,989914h call 76A874F1 mov dword ptr [ebp-4],eax mov ecx,dword ptr [ebp-8] call dword ptr [ebp-4] The extra code appears to be looking up a dynamic vtbl according to the generic parameters, and then calling into it. Has anyone written about the specifics of this implementation? How well does it perform compared to the non-generic case?

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• Java - Call to start method on thread : how does it route to Runnable interface's run () ?

  - by Bhaskar

  Ok , I know the two standard ways to create a new thread and run it in Java : 1 Implement Runnable in a class , define run method ,and pass an instance of the class to a new Thread. When the start method on the thread instance is called , the run method of the class instance will be invoked. 2 Let the class derive from Thread, so it can to override the method run() and then when a new instance's start method is called , the call is routed to overridden method. In both methods , basically a new Thread object is created and its start method invoked. However , while in the second method , the mechanism of the call being routed to the user defined run() method is very clear ,( its a simple runtime polymorphism in play ), I dont understand how the call to start method on the Thread object gets routed to run() method of the class implementing Runnable interface. Does the Thread class have an private field of Type Runnable which it checks first , and if it is set then invokes the run method if it set to an object ? that would be a strange mechanism IMO. How does the call to start() on a thread get routed to the run method of the Runnable interface implemented by the class whose object is passed as a parameter when contructing the thread ?

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• Parallel Tasking Concurrency with Dependencies on Python like GNU Make

  - by Brian Bruggeman

  I'm looking for a method or possibly a philosophical approach for how to do something like GNU Make within python. Currently, we utilize makefiles to execute processing because the makefiles are extremely good at parallel runs with changing single option: -j x. In addition, gnu make already has the dependency stacks built into it, so adding a secondary processor or the ability to process more threads just means updating that single option. I want that same power and flexibility in python, but I don't see it. As an example: all: dependency_a dependency_b dependency_c dependency_a: dependency_d stuff dependency_b: dependency_d stuff dependency_c: dependency_e stuff dependency_d: dependency_f stuff dependency_e: stuff dependency_f: stuff If we do a standard single thread operation (-j 1), the order of operation might be: dependency_f -> dependency_d -> dependency_a -> dependency_b -> dependency_e \ -> dependency_c For two threads (-j 2), we might see: 1: dependency_f -> dependency_d -> dependency_a -> dependency_b 2: dependency_e -> dependency_c Does anyone have any suggestions on either a package already built or an approach? I'm totally open, provided it's a pythonic solution/approach. Please and Thanks in advance!

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• What is the merit of the "function" type (not "pointer to function")

  - by anatolyg

  Reading the C++ Standard, i see that there are "function" types and "pointer to function" types: typedef int func(int); // function typedef int (*pfunc)(int); // pointer to function typedef func* pfunc; // same as above I have never seen the function types used outside of examples (or maybe i didn't recognize their usage?). Some examples: func increase, decrease; // declares two functions int increase(int), decrease(int); // same as above int increase(int x) {return x + 1;} // cannot use the typedef when defining functions int decrease(int x) {return x - 1;} // cannot use the typedef when defining functions struct mystruct { func add, subtract, multiply; // declares three member functions int member; }; int mystruct::add(int x) {return x + member;} // cannot use the typedef int mystruct::subtract(int x) {return x - member;} int main() { func k; // the syntax is correct but the variable k is useless! mystruct myobject; myobject.member = 4; cout << increase(5) << ' ' << decrease(5) << '\n'; // outputs 6 and 4 cout << myobject.add(5) << ' ' << myobject.subtract(5) << '\n'; // 9 and 1 } Seeing that the function types support syntax that doesn't appear in C (declaring member functions), i guess they are not just a part of C baggage that C++ has to support for backward compatibility. So is there any use for function types, other than demonstrating some funky syntax?

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• Query String to Object with strongly typed properties

  - by Kamar

  Let’s say we track 20 query string parameters in our site. Each request which comes will have only a subset of those 20 parameters. But we definitely look for all/most of the parameters which comes in each request. We do not want to loop through the collection each time we are looking for a particular parameter initially or somewhere down the pipeline in the code. So we loop once through the query string collection, convert string values to their respective types (enums, int, string etc.), populate to QueryString object which is added to the context. After that wherever its needed we will have a strongly typed properties in the QueryString object which is easy to use and we maintain a standard. public class QueryString { public int Key1{ get; private set; } public SomeType Key2{ get; private set; } private QueryString() { } public static QueryString GetQueryString() { QueryString l_QS = new QueryString(); foreach (string l_Key in HttpContext.Current.Request.QueryString.AllKeys) { switch (l_Key) { case "key1": l_QS.Key1= DoSomething(l_Key, HttpContext.Current.Request.QueryString[l_Key]); break; case "key2": l_QS.Key2 = DoAnotherThing(l_Key, HttpContext.Current.Request.QueryString[l_Key]); break; } } return l_QS; } } Any other solution to achieve this?

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• Test if Java trusts an SSL certificate

  - by Eric R. Rath

  My java web application uses the standard mail libraries to establish an IMAPS connection to a mail server under my control. The mail server used a valid SSL cert issued by a CA. When the cert expired, I renewed it from the same CA, and put the cert into use. But my web application wouldn't trust the new cert. We had never explicitly trusted the old cert, or managed any trust stores. I talked with someone from the CA, and we tracked it down to a difference in the intermediate certs between the old and new cert. The old one used multiple intermediates, including one tied to a root that must've been trusted by default by our version of Java. The new cert used only one intermediate cert, and it was tied to a root missing from our Java version's default trusted cert store. When we renew this cert again in the future, is there an easy way, given a new crt and intermediate crt file, test if Java will consider that cert valid? I didn't see anything in keytool that looked promising. A code solution is okay, but I'd prefer one based on the Java command-line tools.

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