TestMutex.cpp

#include "stdafx.h"
#include <Windows.h>

static HANDLE s_mutex;

bool lock() {
    s_mutex = CreateMutex(NULL, TRUE, L"TextMutex");
    if (!s_mutex) {
        fprintf(stderr, "CreateMutex failed %d\n", GetLastError());
        return false;
    }
    if (GetLastError() == ERROR_ALREADY_EXISTS) {
        unsigned long ret = WaitForSingleObject(s_mutex, 1000 * 10);
        if (ret != WAIT_OBJECT_0) {
            fprintf(stderr, "WaitForSingleObject failed %d, %d\n", ret, GetLastError());
            return false;
        }
    }
    return true;
}

void unlock() {
    if (!s_mutex) {
        return;
    }
    if (!ReleaseMutex(s_mutex)) {
        fprintf(stderr, "ReleaseMutex failed %d\n", GetLastError());
    }
}

int _tmain(int argc, _TCHAR* argv[]) {
    if (lock()) {
        fprintf(stderr, "sleeping...\n");
        Sleep(1000 * 10);
        fprintf(stderr, "wake up\n");
    }
    unlock();
    CloseHandle(s_mutex);
    return 0;
}

TestMutex2.cpp

#include "stdafx.h"
#include <Windows.h>

static HANDLE s_mutex;

static bool DoLong() {
    fprintf(stderr, "DoLong\n");
    s_mutex = CreateMutex(NULL, FALSE, L"MutexDemo");
    if (!s_mutex) {
        fprintf(stderr, "DoLong: CreateMutex failed %d\n", GetLastError());
        return false;
    }
    DWORD ret = WaitForSingleObject(s_mutex, INFINITE);
    switch (ret) {
    case WAIT_ABANDONED:
        fprintf(stderr, "DoLong: WaitForSingleObject failed WAIT_ABANDONED\n");
        return false;
    case WAIT_TIMEOUT:
        fprintf(stderr, "DoLong: WaitForSingleObject failed WAIT_TIMEOUT\n");
        return false;
    case WAIT_FAILED:
        fprintf(stderr, "DoLong: WaitForSingleObject failed %d\n", GetLastError());
        return false;
    case WAIT_OBJECT_0:
    default:
        fprintf(stderr, "sleeping...\n");
        Sleep(1000 * 10);
        return true;
    }
}

static bool DoShort() {
    fprintf(stderr, "DoShort\n");
    s_mutex = CreateMutex(NULL, FALSE, L"MutexDemo");
    if (!s_mutex) {
        fprintf(stderr, "DoLong: CreateMutex failed %d\n", GetLastError());
        return false;
    }
    DWORD ret = WaitForSingleObject(s_mutex, 1000 * 5);
    switch (ret) {
    case WAIT_ABANDONED:
        fprintf(stderr, "DoLong: WaitForSingleObject failed WAIT_ABANDONED\n");
        return false;
    case WAIT_TIMEOUT:
        fprintf(stderr, "DoLong: WaitForSingleObject failed WAIT_TIMEOUT\n");
        return false;
    case WAIT_FAILED:
        fprintf(stderr, "DoLong: WaitForSingleObject failed %d\n", GetLastError());
        return false;
    case WAIT_OBJECT_0:
    default:
        return true;
    }
}

static bool DoDouble() {
    fprintf(stderr, "DoDouble\n");
    s_mutex = CreateMutex(NULL, FALSE, L"MutexDemo");
    if (!s_mutex) {
        fprintf(stderr, "DoLong: CreateMutex failed %d\n", GetLastError());
        return false;
    }
    if (GetLastError() == ERROR_ALREADY_EXISTS) {
        fprintf(stderr, "CreateMutex failed ERROR_ALREADY_EXISTS\n");
        return false;
    }
    DWORD ret = WaitForSingleObject(s_mutex, 1000 * 5);
    switch (ret) {
    case WAIT_ABANDONED:
        fprintf(stderr, "DoLong: WaitForSingleObject failed WAIT_ABANDONED\n");
        return false;
    case WAIT_TIMEOUT:
        fprintf(stderr, "DoLong: WaitForSingleObject failed WAIT_TIMEOUT\n");
        return false;
    case WAIT_FAILED:
        fprintf(stderr, "DoLong: WaitForSingleObject failed %d\n", GetLastError());
        return false;
    case WAIT_OBJECT_0:
    default:
        return true;
    }
}

int _tmain(int argc, _TCHAR* argv[]) {
    switch (argv[1][0]) {
    case '0':
        if (!DoLong()) {
            return EXIT_FAILURE;
        }
        break;
    case '1':
        if (!DoShort()) {
            return EXIT_FAILURE;
        }
        break;
    case '2':
        if (!DoDouble()) {
            return EXIT_FAILURE;
        }
        break;
    default:
        break;
    }
    if (s_mutex) {
        if (!ReleaseMutex(s_mutex)) {
            fprintf(stderr, "ReleaseMutex failed %d\n", GetLastError());
        }
        CloseHandle(s_mutex);
    }
    fprintf(stderr, "ReleaseMutex\n");
    Sleep(1000 * 5);
    return EXIT_SUCCESS;
}