c++

The importance of knowing c++ for web application development

I'm a php developer and I want to broaden my knowledge base by learning a higher language (java, c#, c++). My specialty is in building web applications (ria etc). I'm trying to think of the appropriate path to take (hedging my bets so to speak) in terms of which language I should be focusing on. I love open source technology but at the s...

How to pass parameters with spaces via cstdlib system

Hi, I have this windows console app which takes a file, do some calculations, and then writes the output to a specified file. The input is specified in "app.exe -input fullfilename" format. I need to call this application from my C++ program, but I have a problem with spaces in paths to files. When I call the app directly from cmd.exe b...

Better cout a.k.a coutn;

Guys would it be difficult to write coutn which would basically place newline symbol at the end of the input. While working with console (that's all I can do at the moment) I'm finding very tedious to write '\n' every time I want the line to be a new line. Or maybe it is already implemented? ...

What -W values in gcc correspond to which actual warnings?

Preamble: I know, disabling warnings is not a good idea. Anyway, I have a technical question about this. Using GCC 3.3.6, I get the following warning: choosing ... over ... because conversion sequence for the argument is better. Now, I want to disable this warning as described in gcc warning options by providing an argument like -...

Eclipse IDE for C/C++ Developers Compile Question

I am using Eclipse IDE for C/C++ Developers, and i am using the gcc to compile at the moment. How can i change it to compile with a Green Hills compiler? Any help will be appreciated. Thanks! ...

How to convert an existing callback interface to use boost signals & slots

I've currently got a class that can notify a number of other objects via callbacks: class Callback { virtual NodulesChanged() =0; virtual TurkiesTwisted() =0; }; class Notifier { std::vector<Callback*> m_Callbacks; void AddCallback(Callback* cb) {m_Callbacks.push(cb); } ... void ChangeNodules() { for (iterator it=m...

How to check if a process is running or got segfaulted or terminated in linux from its pid in my main() in c++

Hello all, I am invoking several processes in my main and I can get the pid of that processes. Now I want to wait until all this processes have been finished and then clear the shared memory block from my parent process. Also if any of the process not finished and segfaulted I want to kill that process. So how to check from the pid of p...

How to get number of bytes read from QTextStream

The following code I am using to find the number of read bytes from QFile. With some files it gives the correct file size, but with some files it gives me a value that is approximatively fileCSV.size()/2. I am sending two files that have same number of characters in it, but have different file sizes link text. Should i use some other obj...

run-time error and program crash

Hi! How can I specify a separate function which will be called automatically at Run-Time error to prevent program crash? ...

Does Qt support virtual pure slots ?

Hi, My GUI project in Qt has a lot of "configuration pages" classes which all inherit directly from QWidget. Recently, I realized that all these classes share 2 commons slots (loadSettings() and saveSettings()). Regarding this, I have two questions: Does it make sense to write a intermediate base abstract class (lets name it BaseCon...

Bidirectional iterators in unordered_map ?

The following minimal example: #include <iostream> #include <boost/unordered_map.hpp> int main() { boost::unordered_map<int, int> m; boost::unordered_map<int, int>::const_iterator i; m.insert(std::make_pair(1, 2)); i = m.end(); --i; std::cout << i->first << " -> " << i->second << std:...

prefill a std::vector at initialization?

I want to create a vector of vector of a vector of double and want it to already have (32,32,16) elements, without manually pushing all of these back. Is there a way to do it during initialization? (I dont care what value gets pushed) Thanks I want a 3 dimensional array, first dimension has 32, second dimension has 32 and third dimensi...

How do you send a named pipe string from umnanaged to managed code space?

I appear to have a named pipes 101 issue. I have a very simple set up to connect a simplex named pipe transmitting from a C++ unmanaged app to a C# managed app. The pipe connects, but I cannot send a "message" through the pipe unless I close the handle which appears to flush the buffer and pass the message through. It's like the message ...

How to read direct3d texture pixels

So I have a x8r8g8b8 formatted IDirect3DSurface9 that contains the contents of the back buffer. When I call LockRect on it I get access to a struct containing pBits, a pointer to the pixels I assume, and and integer Pitch (which I am very unclear about its purpose). How to read the individual pixels? Visual Studio 2008 C++ ...

uh-oh windows mobile threading issues !

specifically WM6x, winCE5x Now my current understanding from trawling the msdn etal is that the IMAPIAdviseSink::OnNotify callback can be made from any old thread; from (ce)mapi or perhaps even from a third-party service provider. Under WM6x, i cannot seem to coax an in-thread response by invoking HrThisThreadAdviseSink, since while th...

How to add a 'or' condition in #ifdef

Hi, How can I add a 'or' condition in #ifdef ? I have tried " #ifdef CONDITION1 || CONDITION2 #endif This does not work. ...

Translating 3-dimensional array reference onto 1-dimensional array

If there is an array of ar[5000] then how could I find where element [5][5][4] would be if this was a 3 dimensional array? Thanks I'm mapping pixels: imagine a bimap of [768 * 1024 * 4] where would pixel [5][5][4] be? I want to make this: static GLubyte checkImage[checkImageHeight][checkImageWidth][4]; static GLuint texName; bool itt...

Internal "Tee" setup

I have inherited some really old VC6.0 code that I am upgrading to VS2008 for building a 64-bit app. One required feature that was implemented long, long ago is overriding std::cout so its output goes simultaneously to a console window and to a file. The implementation depended on the then-current VC98 library implementation of ostream...

generating random enums

How do I randomly select a value for an enum type in C++? I would like to do something like this. enum my_type(A,B,C,D,E,F,G,h,J,V); my_type test(rand() % 10); But this is illegal... there is not an implicit conversion from int to an enum type. ...

Print numbers sequentially using printf with filling zeroes

Hi, in C++, using printf I want to print a sequence of number, so I get, from a "for" loop; 1 2 ... 9 10 11 and I create files from those numbers. But when I list them using "ls" I get 10 11 1 2 .. so instead of trying to solve the problem using bash, I wonder how could I print; 0001 0002 ... 0009 0010 0011 and so on Thanks ...