Multithreaded Programming Guide

Initialize a Mutex Attribute Object


Use pthread_mutexattr_init(3T) to initialize attributes associated with this object to their default values. Storage for each attribute object is allocated by the threads system during execution.

The default value of the pshared attribute when this function is called is PTHREAD_PROCESS_PRIVATE, which means that the initialized mutex can be used within a process.

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

pthread_mutexattr_t mattr;
int ret;

/* initialize an attribute to default value */
ret = pthread_mutexattr_init(&mattr); 

mattr is an opaque type that contains a system-allocated attribute object. The possible values of mattr's scope are PTHREAD_PROCESS_PRIVATE (the default) and PTHREAD_PROCESS_SHARED.

Before a mutex attribute object can be reinitialized, it must first be destroyed by a call to pthread_mutexattr_destroy(3T). The pthread_mutexattr_init() call results in the allocation of an opaque object. If the object is not destroyed, a memory leak will result.

Return Values

Returns zero after completing successfully. Any other returned value indicates that an error occurred. If either of the following conditions occurs, the function fails and returns the corresponding value.


There is not enough memory to initialize the mutex attributes object.