SDL-mirror/src/thread/windows/SDL_sysmutex.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2011 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Mutex functions using the Win32 API */

#include "../../core/windows/SDL_windows.h"

#include "SDL_mutex.h"


struct SDL_mutex
{
    HANDLE id;
};

/* Create a mutex */
SDL_mutex *
SDL_CreateMutex(void)
{
    SDL_mutex *mutex;

    /* Allocate mutex memory */
    mutex = (SDL_mutex *) SDL_malloc(sizeof(*mutex));
    if (mutex) {
        /* Create the mutex, with initial value signaled */
        mutex->id = CreateMutex(NULL, FALSE, NULL);
        if (!mutex->id) {
            SDL_SetError("Couldn't create mutex");
            SDL_free(mutex);
            mutex = NULL;
        }
    } else {
        SDL_OutOfMemory();
    }
    return (mutex);
}

/* Free the mutex */
void
SDL_DestroyMutex(SDL_mutex * mutex)
{
    if (mutex) {
        if (mutex->id) {
            CloseHandle(mutex->id);
            mutex->id = 0;
        }
        SDL_free(mutex);
    }
}

/* Lock the mutex */
int
SDL_mutexP(SDL_mutex * mutex)
{
    if (mutex == NULL) {
        SDL_SetError("Passed a NULL mutex");
        return -1;
    }
    if (WaitForSingleObject(mutex->id, INFINITE) == WAIT_FAILED) {
        SDL_SetError("Couldn't wait on mutex");
        return -1;
    }
    return (0);
}

/* Unlock the mutex */
int
SDL_mutexV(SDL_mutex * mutex)
{
    if (mutex == NULL) {
        SDL_SetError("Passed a NULL mutex");
        return -1;
    }
    if (ReleaseMutex(mutex->id) == FALSE) {
        SDL_SetError("Couldn't release mutex");
        return -1;
    }
    return (0);
}

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