Windows Thread Manipulation - MSDN Documentation

Thread Manipulation

Suspend and Resume

Windows provides SuspendThread and ResumeThread APIs to temporarily pause and continue a thread's execution.

#include <windows.h>

DWORD WINAPI ThreadFunc(LPVOID lpParam) {
    for (int i = 0; i < 10; ++i) {
        Sleep(500);
        printf("Count: %d\n", i);
    }
    return 0;
}

int main() {
    HANDLE hThread = CreateThread(NULL, 0, ThreadFunc, NULL, 0, NULL);
    Sleep(2000);
    SuspendThread(hThread);
    printf("Thread suspended.\n");
    Sleep(2000);
    ResumeThread(hThread);
    printf("Thread resumed.\n");
    WaitForSingleObject(hThread, INFINITE);
    CloseHandle(hThread);
    return 0;
}

Setting Thread Priority

Adjust a thread's priority using SetThreadPriority and retrieve current priority with GetThreadPriority.

Priority Constant	Description
THREAD_PRIORITY_LOWEST	Lowest possible priority.
THREAD_PRIORITY_BELOW_NORMAL	Below normal priority.
THREAD_PRIORITY_NORMAL	Default priority.
THREAD_PRIORITY_ABOVE_NORMAL	Above normal priority.
THREAD_PRIORITY_HIGHEST	Highest possible priority.

#include <windows.h>

HANDLE hThread = CreateThread(NULL, 0, SomeFunc, NULL, 0, NULL);
if (hThread) {
    SetThreadPriority(hThread, THREAD_PRIORITY_ABOVE_NORMAL);
    DWORD prio = GetThreadPriority(hThread);
    printf("Current priority: %lu\n", prio);
    CloseHandle(hThread);
}

Thread Affinity

Control the processor(s) a thread can run on using SetThreadAffinityMask.

#include <windows.h>

DWORD WINAPI Work(LPVOID) {
    for (;;) {
        // intensive work
    }
    return 0;
}

int main() {
    HANDLE h = CreateThread(NULL, 0, Work, NULL, 0, NULL);
    // Restrict to CPU 0
    SetThreadAffinityMask(h, 0x1);
    WaitForSingleObject(h, INFINITE);
    CloseHandle(h);
    return 0;
}

Forceful Termination (Deprecated)

While TerminateThread can abruptly end a thread, it is discouraged due to resource leaks. Use cooperative cancellation instead.

#include <windows.h>

void StopThread(HANDLE hThread) {
    // Not recommended
    TerminateThread(hThread, 0);
}