How do I pass data to different threads

Suppose If I create 5 thre开发者_运维百科ads through CreateThread(). I'll need to pass intergers 1, 2, 3, 4, 5 to each thread but I also have to pass a this pointer. Neither I can pass more than one argument because CreateThread function takes only one, nor I can create a member variable in class because that will be shared between the threads. How can do it and how much data can a thread stack have?

Define a struct and pass an object of this struct.

The struct can be this:

struct ThreadContext
{
     MyClass *m_this;
     int      m_int;
     //add more members you need to pass more data
};

Then you can do this:

for ( int i = 0 ; i < 5 ; i++ )
{
   ThreadContext *ctx = new ThreadContext();
   ctx->m_this = this;
   ctx->m_int = i ;
   CreateThread(...., ThreadProc, ctx, ...);
}

Make sure that the object you pass to each thread is different object. That is why I used new and created an object for each thread. And then inside the ThreadFunc, use static_cast as:

DWORD WINAPI ThreadProc(LPVOID lpParameter)
{
     ThreadContext *ctx = static_cast<ThreadContext*>(lpParameter);
     //use ctx

     //...

     //at the end of the thread, deallocate the memory!
     delete ctx; 
}

Or alternatively, you could maintain a std::vector<ThreadContext> as member data of MyClass.

Maybe create a new struct containing a this pointer and an integer, and pass that to the thread, extracting these contents appropriately in the function that the thread runs?