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(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+
SEE ALSO
pthread_cond_init(3C),
pthread_create(3C),
pthread_mutex_init(3C),
pthread_mutexattr_init(3C),
attributes(7),
standards(7) March 23, 2005
PTHREAD_MUTEXATTR_GETPSHARED(3C)
