sending arguments to function using CreateThread

This is a discussion on sending arguments to function using CreateThread within the C++ Programming forums, part of the General Programming Boards category; Is there any way to send more then one parameter to a function using CreateThread. Code: #include <iostream> #include <windows.h> ...

  1. #1
    Registered User Micko's Avatar
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    sending arguments to function using CreateThread

    Is there any way to send more then one parameter to a function using CreateThread.

    Code:
    #include <iostream>
    #include <windows.h>
    using namespace std;
    
    void Func(int *, double);
    
    int main()
    {
    	DWORD ThreadID;
    	int x=1;
    	double y=5.23;
    	HANDLE hThread=CreateThread(0,0,(LPTHREAD_START_ROUTINE)Func,(int *)&x,0,&ThreadID);
    	WaitForSingleObject(hThread,INFINITE);
    	return 0;
    }
    
    
    void Func(int *i,double d)
    {
    	cout<<"Values are: "<<*i<<" i "<<d<<endl;
    }

  2. #2
    Compulsive Liar Robc's Avatar
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    The parameter is a pointer to void, you can send whatever you like if you're sufficiently creative. For example, pass a structure with members representing your arguments.

  3. #3
    Magically delicious LuckY's Avatar
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    Posts
    856
    What robc said is what is always done. For example (for those who are not as sufficiently creative as Robc suggests), your program would look like this:
    Code:
    #include <iostream>
    #include <windows.h>
    using namespace std;
    
    void Func(LPVOID pArgs_);
    
    struct ARGS {
      int *i;
      double d;
    };
    
    int main()
    {
      DWORD ThreadID;
      int x=1;
      double y=5.23;
      ARGS args = { &x, y };
      HANDLE hThread=CreateThread(0,0,(LPTHREAD_START_ROUTINE)Func,&args,0,&ThreadID);
    	WaitForSingleObject(hThread,INFINITE);
    	return 0;
    }
    
    
    void Func(LPVOID pArgs_)
    {
      ARGS *pArgs = (ARGS*)pArgs_;
      cout<<"Values are: "<<*pArgs->i<<" i "<<pArgs->d<<endl;
    }

  4. #4
    Yes, my avatar is stolen anonytmouse's Avatar
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    2,544
    The only correct prototype for a thread entry function is:
    Code:
    DWORD CALLBACK ThreadProc(LPVOID lpParameter);
    If you have to cast your thread function, you are doing something very wrong.

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