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Shilo Sogauker
Shilo Sogauker

Reputation: 13

How to close Thread by using the library windows.h (in c)

I wish to create a Thread that will always run until I force him to be close. I programming in c language, and uses the library windows.h adding my code of creating thread:

HANDLE thread;
DWORD threadID;
thread = CreateThread(NULL, 0, infinitePlay, (void*)*head, 0, &threadID);
if (thread)
{
   // doing some work or just waiting           
}

Upvotes: 0

Views: 150

Answers (1)

AdamF
AdamF

Reputation: 2940

In one word (short answer), you need to call the BOOL TerminateThread(HANDLE hThread, DWORD dwExitCode); see microsoft docs in the link term_thread function and pass to it in the hThread param the return thread from CreateThread function in your case it is thread

for long answer

consider the thread function ThreadRoutine below:

#include <windows.h>
DWORD WINAPI ThreadRoutine(void* data) {
  /*Creates a thread to execute within the virtual address space of the calling process.
 this function will be passed later as a functio pointer to CreateThread which will be the  the application-defined function to be executed by the thread.*/

    return 0;
}

Now this is the CreateThread function from microsoft_docs

HANDLE CreateThread(
  LPSECURITY_ATTRIBUTES   lpThreadAttributes,
  SIZE_T                  dwStackSize,
  LPTHREAD_START_ROUTINE  lpStartAddress,
  __drv_aliasesMem LPVOID lpParameter,
  DWORD                   dwCreationFlags,
  LPDWORD                 lpThreadId
);

Function arguments

lpThreadAttributes: If lpThreadAttributes is NULL, the handle cannot be inherited by child processes.

dwStackSize: The initial size of the stack, in bytes. The system rounds this value to the nearest page. If this parameter is zero, the new thread uses the default size for the executable.

**lpStartAddress**: A pointer to the application-defined function to be executed by the thread. This pointer represents the starting address of the thread. in our case its the ThreadRoutine.

lpParameter: A pointer to a variable to be passed to the thread. we can pass in void* what ever we like to pass since its a generic pointer.

dwCreationFlags: The flags that control the creation of the thread.

lpThreadId: A pointer to a variable that receives the thread identifier. If this parameter is NULL, the thread identifier is not returned.

return value If the function succeeds, the return value is a handle to the new thread. If the function fails, the return value is NULL.

Killing the thread we have created:

BOOL TerminateThread(HANDLE hThread, DWORD  dwExitCode);

TerminateThread is used to cause a thread to exit. When this occurs, the target thread has no chance to execute any user-mode code. DLLs attached to the thread are not notified that the thread is terminating. The system frees the thread's initial stack. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero.

So after reviewing all CreateThread arguments, we will use the the form below:

int main() {
  HANDLE t_thread = CreateThread(NULL, 0, ThreadRoutine, NULL, 0, NULL);
  if (t_thread ) {
    // Optionally do stuff, such as wait on the thread or ...

    /*After some time lets kill or terminate the thread we have created*/
    BOOL re_term =TerminateThread(t_thread , DWORD  dwExitCode);
    if(re_term == 0){  //failed
       /*maybe you should call GetLastError function*/
    }
    else{ 
       /*killed successefully*/
    }

  }
  
  return 0;
}

Upvotes: 1

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