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passing parrameters to a new thread

For Beginners

Started by crazy_andy January 03, 2005 08:41 AM

3 comments, last by crazy_andy 19 years, 3 months ago

crazy_andy

100

Author

January 03, 2005 08:41 AM

using AfxBeginThread() I need to pass the array c[2] to a new thread. How can I do this, I have googled it but not found anything clear.

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evolutional

1,397

January 03, 2005 08:56 AM

The function prototype:

CWinThread* AfxBeginThread( AFX_THREADPROC pfnThreadProc, LPVOID pParam, int nPriority = THREAD_PRIORITY_NORMAL, UINT nStackSize = 0, DWORD dwCreateFlags = 0, LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL );

One of the parameters is

LPVOID pParam

, which allows the user to pass one parameter of any type to the thread. So, in order to pass multiple parameters, you will need to create a struct (or class) to hold the parameters and then pass the address of an instance of this data to the function instead.

An example to illustrate:

struct myThreadParams{  int c[2];  int ca[2];  char *someString;};// Some of your code:myThreadParams *params = new myThreadParams;params->someString = "hello";params->c[0] = 1; params->c[3] = 2;// Pass the param to the thread;CWinThread *thread = AfxBeginThread( &MyThreadProc, params, /* rest are default values */ );

When the thread is running, it will have access to the data you passed as a parameter, but remember to use it, you'll need to cast it to the relevant type:

UINT MyThreadProc(  LPVOID pParam ){  myThreadParams *params = static_cast<myThreadParams *>( pParam );  MessageBox( params->someString );  return 0;}

crazy_andy

100

Author

January 03, 2005 01:11 PM

cheers, by the way, what is the cast for a socket. as in SOCKET c[2].

edit: rather than create a new thread, can someone show me how to do this please:

I have

char temp[512];
cin >> temp; //user types in exit

if (temp == "exit")
{
...
}
return;

I know this is basic, but I can't remember it. When I run this and type exit it doesn't do anything, it just skips, and Im not sure why.

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