PTHREAD_RWLOCKATTR_GETPSHARED(3C)PTHREAD_RWLOCKATTR_GETPSHARED(3C)NAME
pthread_rwlockattr_getpshared, pthread_rwlockattr_setpshared - get or
set process-shared attribute of read-write lock attributes object
SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ]
#include <pthread.h>
int pthread_rwlockattr_getpshared(
const pthread_rwlockattr_t *restrict attr,
int *restrict pshared);
int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr,
int pshared);
DESCRIPTION
The process-shared attribute is set to PTHREAD_PROCESS_SHARED to per‐
mit a read-write lock to be operated upon by any thread that has access
to the memory where the read-write lock is allocated, even if the
read-write lock is allocated in memory that is shared by multiple pro‐
cesses. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE,
the read-write lock will only be operated upon by threads created
within the same process as the thread that initialised the read-write
lock; if threads of differing processes attempt to operate on such a
read-write lock, the behaviour is undefined. The default value of the
process-shared attribute is PTHREAD_PROCESS_PRIVATE.
The pthread_rwlockattr_getpshared() function obtains the value of the
process-shared attribute from the initialised attributes object refer‐
enced by attr. The pthread_rwlockattr_setpshared() function is used to
set the process-shared attribute in an initialised attributes object
referenced by attr.
RETURN VALUES
If successful, the pthread_rwlockattr_setpshared() function returns 0.
Otherwise, an error number is returned to indicate the error.
Upon successful completion, the pthread_rwlockattr_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.
ERRORS
The pthread_rwlockattr_getpshared() and pthread_rwlockattr_setpshared()
functions will fail if:
EINVAL
The value specified by attr or pshared is invalid.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOpthread_rwlock_init(3C), pthread_rwlock_rdlock(3C),
pthread_rwlock_unlock(3C), pthread_rwlock_wrlock(3C), pthread_rwlock‐
attr_init(3C), attributes(5), standards(5)
Mar 23, 2005PTHREAD_RWLOCKATTR_GETPSHARED(3C)
