c++

Avoding multiple thread spawns in pthreads

Hi StackOverflow, I have an application that is parallellized using pthreads. The application has a iterative routine call and a thread spawn within the rountine (pthread_create and pthread_join) to parallelize the computation intensive section in the routine. When I use an instrumenting tool like PIN to collect the statistics the tool ...

whats the differnce between dot operator and scope resolution operator

I just wanted to know the difference between . operator and :: operator? ...

How to replace all occurrences of a character in string?

What is the effective way to replace all occurrences of a character with another character in std::string? ...

Is there open-source java/c/c++ framework for pipes-and-filters paradigm?

I'm interested in open-source Java/C/C++ framework for pipes-and-filters (like described in that book) paradigm. Can you recommend some? EDIT: I'm looking for as much "pure" (or lightweight) frameworks as possible: frameworks which encourage programming in "pipes-and-filters" technique, without reliance on any standards, such as XML or ...

dereferencing the null pointer

int* p = 0; int* q = &*p; Is this undefined behavior or not? I browsed some related questions, but this specific aspect didn't show up. ...

XmlHttpRequest bug?

Hello all. I'm writing a program that among other things needs to download a file given its URL. I'm too lazy to implement the Http/Https protocols manually, so that I needed some library/object/function that'll do the job. Critical requirement: The download must be asynchronous. That is, the thread that issued the download must be abl...

Windowless OpenGL

Hi, I would like to have a windowless OpenGL context (on both GNU/linux with Xorg and Windows). I'm not going to render anything but only call functions like glGetString, glCompileShader and similar. I've done some goggling but not come up with anything useful, except creating a hidden window; which seems like a hack to me. So does an...

Sorting a string in array, making it sparsely populated.

For example, say I have string like: duck duck duck duck goose goose goose dog And I want it to be as sparsely populated as possible, say in this case duck goose duck goose dog duck goose duck What sort of algorithm would you recommend? Snippets of code or general pointers would be useful, languages welcome Python, C++ and extra k...

wchar to char in c++

I have a Windows CE console application that's entry point looks like this int _tmain(int argc, _TCHAR* argv[]) I want to check the contents of argv[1] for "-s" convert argv[2] into an integer. I am having trouble narrowing the arguments or accessing them to test. I initially tried the following with little success if (argv[1] ==...

header confusion. Compiler not recognizing datatypes

I am getting confused on why the compiler is not recognizing my classes. So I am just going to show you my code and let you guys decide. My error is this error C2653: 'RenderEngine' : is not a class or namespace name and it's pointing to this line std::vector<RenderEngine::rDefaultVertex> m_verts; Here is the code for rModel, in i...

writing XML with Xerces 3.0.1 and C++ on windows

Hi, i have the following function i wrote to create an XML file using Xerces 3.0.1, if i call this function with a filePath of "foo.xml" or "../foo.xml" it works great, but if i pass in "c:/foo.xml" then i get an exception on this line XMLFormatTarget *formatTarget = new LocalFileFormatTarget(targetPath); can someone explain why my co...

C++ question on file formats and od

I have the following simple code: ofstream output("test"); output << 'a'; When I do an octal dump of the file, I get this: 0000000 000141 0000001 I can see that 000141 (in base 8) is 8 bits wide and 0000001 is probably EOF. What is the first byte of all 0's and why is it there? I know it is null is ascii but what is its purpose? ...

How to change the meaning of pointer access operator

Hi All, This may be very obvious question, pardon me if so. I have below code snippet out of my project, #include <stdio.h> class X { public: int i; X() : i(0) {}; }; int main(int argc,char *arv[]) { X *ptr = new X[10]; unsigned index = 5; cout<<ptr[index].i<<endl; return 0; } Question Can I change the meaning of...

can i braodcast a UDP package to part of a network ?

i am trying to broadcast a UDP package using subnet. i want to braodcast my package to 192.168.1.255 ? can i do that ? and how using c++ ? ...

Pseudo code for instruction description

Hi, I am just trying to fiddle around what is the best and shortest way to describe two simple instructions with C-like pseudo code. The extract instruction is defined as follows: extract rd, rs, imm This instruction extracts the appropriate byte from the 32-bit source register rs and right justifies it in the destination register. T...

How to simulate a file read error in the CRT

Using VS2008, we would like to simulate a file that has a size of X, but that has a read failure at X-Y bytes, so that we get an error indication. Anyone have an idea of how to do this on windows? Looks like there is a solution for linux, but I can't really come up with a way to do this on windows. We have multiple developers, multiple...

How to link openssl crypto lib in C++?

I am trying to test the crypto library that comes with openssl, I downloaded openssl from http://www.openssl.org/source/ and it contains a /crypto folder with subfolders for each encryption type. I wanted to try BIO_f_base64 so I created an empty console app, and added the includes needed, also added the paths to the /bio and /evp folde...

Is it possible to have an out-of-process COM server where a separate O/S process is used for each object instance?

I have a legacy C++ "solution engine" that I have already wrapped as an in-process COM object for use by client applications that only require a single "solution engine". However I now have a client application that requires multiple "solution engines". Unfortunately the underlying legacy code has enough global data, singletons and thre...

Why C++ virtual function defined in header may not be compiled and linked in vtable?

Situation is following. I have shared library, which contains class definition - QueueClass : IClassInterface { virtual void LOL() { do some magic} } My shared library initialize class member QueueClass *globalMember = new QueueClass(); My share library export C function which returns pointer to globalMember - void * getGlobal...

Is rand() predictable in C++

Possible Duplicate: Whats the Right Way to use the rand() Function in C++? When I run the below program I always get the same values each time. Is rand not a true random function? int main() { while(1) { getch(); cout<<rand()<<endl; } } In each run I am getting the below values. 41 18467 6334 26500 19169 1572...