pthread_mutexattr_init() — Initialize a mutex attribute object

Standards

Standards / Extensions	C or C++	Dependencies
POSIX.4a Single UNIX Specification, Version 3	both	POSIX(ON)

Format

#define _OPEN_THREADS
#define _OPEN_SYS
#include <pthread.h>

int pthread_mutexattr_init(pthread_mutexattr_t *attr);

SUSV3:

#define _UNIX03_THREADS
#define _OPEN_SYS
#include <pthread.h>

int pthread_mutexattr_init(pthread_mutexattr_t *attr);

General description

Initializes a mutex attribute object. With a mutex attribute object, you can manage the characteristics of mutexes in your application. It defines the set of values to be used for the mutex during its creation. By establishing a mutex attribute object, you can create many mutexes with the same set of characteristics, without defining those characteristics for each and every mutex.

For a valid mutex attribute, refer to pthread_mutexattr_setkind_np() — Set kind for a mutex attribute object.

Note: Before freeing up the storage containing the pthread_mutexattr_t object, be sure to destroy it by calling pthread_mutexattr_destroy(). If the pthread_mutexattr_t object is not destroyed before the storage is reused, the results are undefined.

Returned value

If successful, pthread_mutexattr_init() returns 0.

If unsuccessful, pthread_mutexattr_init() returns -1 and sets errno to one of the following values:

Error Code: Description
ENOMEM: There is not enough memory to initialize attr.

Special behavior for Single UNIX Specification, Version 3:

If unsuccessful, pthread_mutexattr_init() returns an error number to indicate the error.

Example

CELEBP44

⁄* CELEBP44 *⁄

#define _OPEN_THREADS
#define _OPEN_SYS       ⁄* Needed to identify __MUTEX_RECURSIVE *⁄
#include <pthread.h>
#include <stdio.h>

main() {
  pthread_mutexattr_t attr;
  pthread_mutex_t mutex;

  if (pthread_mutexattr_init(&attr) != 0) {
    perror("pthread_mutex_attr_init() error");
    exit(1);
  }

  if (pthread_mutexattr_setkind_np(&attr, __MUTEX_RECURSIVE) != 0) {
    perror("pthread_mutex_attr_setkind_np() error");
    exit(2);
  }

  if (pthread_mutex_init(&mutex, &attr) != 0) {
    perror("pthread_mutex_init() error");
    exit(3);
  }

  if (pthread_mutexattr_destroy(&attr) != 0) {
    perror("pthread_mutex_attr_destroy() error");
    exit(4);
  }
}