pthread_rwlockattr_getpshared(3) Library Functions Manual pthread_rwlockattr_getpshared(3)NAME
pthread_rwlockattr_getpshared - Obtains the process-shared attribute of a read-write lock attributes object.
LIBRARY
DECthreads POSIX 1003.1c Library (libpthread.so)
SYNOPSIS
#include <pthread.h>
int pthread_rwlockattr_getpshared(
const pthread_rwlockattr_t *attr,
int *pshared);
PARAMETERS
Address of the read-write lock attributes object whose process-shared attribute is to be obtained. Location to store the value of the
process-shared attribute of attr.
DESCRIPTION
This routine obtains the value of the process-shared attribute in the read-write lock attributes object referenced by attr and stores it at
the location pshared. The object referenced by attr must be initialized before this routine is called.
RETURN VALUES
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows:
Successful completion. The value specified by attr is not a valid attributes object.
ERRORS
None
RELATED INFORMATION
Functions: pthread_rwlockattr_setpshared(3), pthread_rwlockattr_init(3)
Manuals: Guide to DECthreads and Programmer's Guide
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pthread_rwlockattr_getpshared(3)
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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);
The process-shared attribute is set to PTHREAD_PROCESS_SHARED to permit 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
processes. 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 ref-
erenced by attr. The pthread_rwlockattr_setpshared() function is used to set the process-shared attribute in an initialised attributes
object referenced by attr.
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.
The pthread_rwlockattr_getpshared() and pthread_rwlockattr_setpshared() functions will fail if:
EINVAL The value specified by attr or pshared is invalid.
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
pthread_rwlock_init(3C), pthread_rwlock_rdlock(3C), pthread_rwlock_unlock(3C), pthread_rwlock_wrlock(3C), pthread_rwlockattr_init(3C),
attributes(5), standards(5)
23 Mar 2005 pthread_rwlockattr_getpshared(3C)