mutex_attr.c

/*
 * mutex_attr.c
 *
 * Create a mutex using a non-default attributes object,
 * mutex_attr. If the implementation supports the pshared
 * attribute, the mutex is created "process private" so that it
 * could be used to synchronize between threads in separate
 * address spaces. (Note that, to create a "process shared"
 * mutex, the pthread_mutex_t itself must be placed in shared
 * memory that is accessible to all threads using the mutex.)
 */
#include <pthread.h>
#include "errors.h"

pthread_mutex_t mutex;

int main (int argc, char *argv[])
{
    pthread_mutexattr_t mutex_attr;
    int status;

    status = pthread_mutexattr_init (&mutex_attr);
    if (status != 0)
        err_abort (status, "Create attr");
#ifdef _POSIX_THREAD_PROCESS_SHARED
    status = pthread_mutexattr_setpshared (
        &mutex_attr, PTHREAD_PROCESS_PRIVATE);
    if (status != 0)
        err_abort (status, "Set pshared");
#endif
    status = pthread_mutex_init (&mutex, &mutex_attr);
    if (status != 0)
        err_abort (status, "Init mutex");
    return 0;
}