pthread_mutexattr_init()--Initialize Mutex Attributes Object

 #include <pthread.h>
 int pthread_mutexattr_init(pthread_mutexattr_t *attr);  

The pthread_mutexattr_init() function initializes the mutex attributes object referenced by attr to the default attributes. The mutex attributes object can be used in a call to pthread_mutex_init() to create a mutex.

Authorities and Locks

None.

Parameters

attr

(Input/Output) Address of the variable to contain the mutex attributes object

Return Value

0

pthread_mutexattr_init() was successful.

value

pthread_mutexattr_init() was not successful. value is set to indicate the error condition.

Error Conditions

If pthread_mutexattr_init() was not successful, the error condition returned usually indicates one of the following errors. Under some conditions, the value returned could indicate an error other than those listed here.

[EINVAL]

The value specified for the argument is not correct.

Related Information

• The <pthread.h> header file. See Header files for Pthread functions.
  
  
• pthread_mutexattr_destroy()--Destroy Mutex Attributes Object
  
  
• pthread_mutex_destroy()--Destroy Mutex
  
  
• pthread_mutex_init()--Initialize Mutex

Example

See Code disclaimer information for information pertaining to code examples.

#include <pthread.h>
#include <stdio.h>
#include "check.h"

pthread_mutex_t    mutex;

int main(int argc, char **argv)
{
  int                   rc=0;
  pthread_mutexattr_t   mta;

  printf("Entering testcase\n");

  printf("Create a default mutex attribute\n");
  rc = pthread_mutexattr_init(&mta);
  checkResults("pthread_mutexattr_init\n", rc);

  printf("Create the mutex using a mutex attributes object\n");
  rc = pthread_mutex_init(&mutex, &mta);
  checkResults("pthread_mutex_init(mta)\n", rc);

  printf("- At this point, the mutex with its default attributes\n");
  printf("- Can be used from any threads that want to use it\n");

  printf("Destroy mutex attribute\n");
  rc = pthread_mutexattr_destroy(&mta);
  checkResults("pthread_mutexattr_destroy()\n", rc);

 
  printf("Destroy mutex\n");
  rc = pthread_mutex_destroy(&mutex);
  checkResults("pthread_mutex_destroy()\n", rc);
 
  printf("Main completed\n");
  return 0;
}

Output:

Entering testcase
Create a default mutex attribute
Create the mutex using a mutex attributes object
- At this point, the mutex with its default attributes
- Can be used from any threads that want to use it
Destroy mutex attribute
Destroy mutex
Main completed