c++

Eliminating inherited overlong MACRO

I have inherited a very long set of macros from some C algorithm code.They basically call free on a number of structures as the function exits either abnormally or normally. I would like to replace these with something more debuggable and readable. A snippet is shown below #define FREE_ALL_VECS {FREE_VEC_COND(kernel);FREE_VEC_COND(cirra...

delete vs NULL vs free in c++

what is the difference between deleting a pointer, setting it to null, and freeing it. delete ptr; vs. ptr=NULL; vs. free(ptr); ...

How do I read long lines from a text file in C++?

I am using the following code for reading lines from a text-file. What is the best method for handling the case where the line is greater than the limit SIZE_MAX_LINE? void TextFileReader::read(string inFilename) { ifstream xInFile(inFilename.c_str()); if(!xInFile){ return; } char acLine[SIZE_MAX_LINE + 1]; ...

How `is_base_of` works?

Why the following code works? typedef char (&yes)[1]; typedef char (&no)[2]; template <typename B, typename D> struct Host { operator B*() const; operator D*(); }; template <typename B, typename D> struct is_base_of { template <typename T> static yes check(D*, T); static no check(B*, int); static const bool value = sizeo...

Turn off the display on remote PC

Hello. I'm fixing some bugs in the application for remote control (remote desktop-like) for Windows. And there is a feature that you can blank screen on remote machine - all the programms keep running unaffected, but the person who looks into the display on remote PC sees nothing but black screen. It is implemented by sending IoCtl requ...

Custom (pool) allocator with boost shared_ptr

I want objects managed by a shared_ptr to be allocated from a pool, say Boost's Pool interface, how can this be achieved? ...

Find the "name" of a library (-L -l switches)

Being fairly new to C++ I have a question bascially concerning the g++ compiler and especially the inclusion of libraries. Consider the following makefile: CPPFLAGS= -I libraries/boost_1_43_0-bin/include/ -I libraries/jpeg-8b-bin/include/ LDLIBS= libraries/jpeg-8b-bin/lib/libjpeg.a # LDLIBS= -L libraries/jpeg-8b-bin/lib -llibjpeg all: ...

Access variable value using string representing variable's name in C++

Hello everyone, If the title was not clear, I will try to clarify what I am asking: Imagine I have a variable called counter, I know I can see its current value by doing something like: std::cout << counter << std::endl; However, assume I have lots of variables and I don't know which I'm going to want to look at until runtime. Doe...

structures, inheritance and definition

Hi, i need to help with structures, inheritance and definition. //define struct struct tStruct1{ int a; }; //definition tStruct1 struct1{1}; and inheritance struct tStruct2:tStruct1{ int b; }; How can I define it in declaration line? tStruct2 struct2{ ????? }; One more question, how can i use inheritance for structures ...

Better name needed for applying a function on elements of a container

I have a container class (containing a multi-index container) for which I have a public "foreach" member-function, so users can pass a functor to apply on all elements. While implementing, I had a case where the functor should only be applied to some elements of a range in the container, so I overloaded the foreach, to pass some valid ra...

MessageBox not shown when opened processing WM_CLOSE from taskbar thumbnail close button

Trying to put up a "Do you want to save"-dialog when trying to close window with close-button in taskbar thumbnail in windows 7(with aero peek active). Using MessageBox() when processing WM_CLOSE does not work. MessageBox won't show until you move mouse cursor outside thumbnail so aero peek is disabled. Lots of applications have this b...

Interrupt mechanism in C,C++

Hey I was writing a udp client server in which a client waits for packets from server.But I want to limit this wait for certain time.After client don't get response for a certain moment in raise an alarm,basically it comes out and start taking remedy steps.So what are the possible solution for it.I think writing a wrapper around recv wil...

crash when using stl vector at instead of operator[]

I have a method as follows (from a class than implements TBB task interface - not currently multithreading though) My problem is that two ways of accessing a vector are causing quite different behaviour - one works and the other causes the entire program to bomb out quite spectacularly (this is a plugin and normally a crash will be caugh...

FFMpeg encoding RGB images to H264

Hello I'm developing a DirectShow filter which has 2 input pins (1 for audio, 1 for video). I'm using libavcodec/libavformat/libavutil of FFMpeg for encoding the video to H264, audio to AAC and mux it/stream using RTP. So far I was able to encode video and audio correctly using libavcodec but now I see that FFMpeg seems to support RTP mu...

Do you know of some performances test of the different ways to get thread local storage in C++?

I'm doing a library that makes extensive use of a thread local variable. Can you point to some benchmarks that test the performances of the different ways to get thread local variables in C++: C++0x thread_local variables compiler extension (Gcc __thread, ...) boost::threads_specific_ptr pthread Windows ... Does C++0x thread_local ...

How to get spacing between characters printed using TextOut ?

I'm trying to calcuate size of each cell (containing text like "ff" or "a0"), so that 32 cells will fit into window by width. However, charWidth*2 doesn' represent the width of a cell, since it doesn't take spacing between characters in the account. How can I obtain size of a font so that 32 cells each is two chars like "ff" fit exactly...

CRXIR2 doesn't work with VS2010 on Windows 7 nor on Vista

We're upgrading from VS2005 to VS2010. We are almost there but there is a problem with Crystal Reports. We use the RDC (COM-based) component within our C++ application. On Windows 7 or on VISTA, I can't get the viewer nor the designer controls working. I get Access Violations when the control is activated: // from atlhost.h (line 2208)...

Strange realloc behaviour

Hi guys, i'm developing an array structure just for fun. This structure, generalized by a template parameter, pre allocates a given number of items at startup, then, if "busy" items are more than available ones, a function will realloc the inner buffer . The testing code is : #include <stdio.h> #include <stdlib.h> #include <string.h> t...

Fast, lightweight HTML parser for C++

I'm looking for a fast, lightweight open-source HTML parser -- something along the lines of a non-validating SAX parser (except, of course, for HTML). The answers to this question cover a parser that generates a DOM (don't want that), and these answers suggest conforming the HTML to XML before sending it to Xerxes (can't do that in my c...

What does this C++ code mean

I was trying to understand how webkit parses urls, and I'm having a hard time making heads or tails of this: Vector<char, 4096> buffer(fragmentEnd * 3 + 1); This line is on line 1214 (you can see it here: http://trac.webkit.org/browser/trunk/WebCore/platform/KURL.cpp#L1214). I get that it's making a vector of type char, with each ent...