PTHREAD_MUTEXATTR_GETPSHARED(3C) Standard C Library Functions


NAME


pthread_mutexattr_getpshared, pthread_mutexattr_setpshared - get or set
process-shared attribute

SYNOPSIS


cc -mt [ flag... ] file... -lpthread [ library... ]
#include <pthread.h>

int pthread_mutexattr_getpshared(
const pthread_mutexattr_t *restrict attr,
int *restrict pshared);


int pthread_mutexattr_setpshared(pthread_mutexattr_t *attr,
int pshared);


DESCRIPTION


The pthread_mutexattr_getpshared() function obtains the value of the
process-shared attribute from the attributes object referenced by attr.
The pthread_mutexattr_setpshared() function is used to set the process-
shared attribute in an initialized attributes object referenced by attr.


The process-shared attribute is set to PTHREAD_PROCESS_SHARED to permit
a mutex to be operated upon by any thread that has access to the memory
where the mutex is allocated, even if the mutex is allocated in memory
that is shared by multiple processes. If the process-shared attribute is
PTHREAD_PROCESS_PRIVATE, the mutex will only be operated upon by threads
created within the same process as the thread that initialized the mutex;
if threads of differing processes attempt to operate on such a mutex, the
behavior is undefined. The default value of the attribute is
PTHREAD_PROCESS_PRIVATE.

RETURN VALUES


Upon successful completion, pthread_mutexattr_getpshared() returns 0 and
stores the value of the process-shared attribute of attr into the object
referenced by the pshared parameter. Otherwise, an error number is
returned to indicate the error.


Upon successful completion, pthread_mutexattr_setpshared() returns 0.
Otherwise, an error number is returned to indicate the error.

ERRORS


The pthread_mutexattr_getpshared() and pthread_mutexattr_setpshared()
functions may fail if:

EINVAL
The value specified by attr is invalid.


The pthread_mutexattr_setpshared() function may fail if:

EINVAL
The new value specified for the attribute is outside the range
of legal values for that attribute.


ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


pthread_create(3C), pthread_mutex_init(3C), pthread_mutexattr_init(3C),
pthread_cond_init(3C), attributes(5), standards(5)


March 23, 2005 PTHREAD_MUTEXATTR_GETPSHARED(3C)