HP-UX Reference (11i v1 05/09) - 3 Library Functions N-Z (vol 7)

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pthread_rwlockattr_init(3T) pthread_rwlockattr_init(3T)
(Pthread Library)
NAME
pthread_rwlockattr_init(), pthread_rwlockattr_destroy() - initialize or destroy a read-write lock attributes
object.
SYNOPSIS
#include <pthread.h>
int pthread_rwlockattr_init(
pthread_rwlockattr_t *attr
);
int pthread_rwlockattr_destroy(
pthread_rwlockattr_t *attr
);
PARAMETERS
attr Pointer to the read-write lock attributes object to be initialized or destroyed.
DESCRIPTION
pthread_rwlockattr_init()
initializes the read-write lock attributes object attr with the default
value for all attributes. The attributes object describes a read-write lock in detail and is passed to the read-
write lock initialization function.
When a read-write lock attributes object is used to initialize a read-write lock, the values of the individual
attributes determine the characteristics of the new read-write lock. Attributes objects act like additional
parameters to object initialization.
After a read-write lock attributes object has been used to initialize one or more read-write lock, any func-
tion affecting the attributes object does not affect the previously initialized read-write locks.
The read-write lock attributes and their default values are:
process-shared The default value is
PTHREAD_PROCESS_PRIVATE.
If an initialized read-write lock attributes object is reinitialized, undefined behavior results.
pthread_rwlockattr_destroy()
destroys the read-write lock attributes object attr. The destroyed
read-write lock attributes object ceases to exist and its resources are reclaimed. Referencing the object after
it has been destroyed results in undefined behavior. A destroyed read-write lock attributes object can be
reinitialized using the function
pthread_rwlockattr_init()
.
Read-write locks which have been already initialized using this attributes object are not affected by the des-
truction of the read-write lock attributes object.
RETURN VALUE
Upon successful completion,
pthread_rwlockattr_init()
and
pthread_rwlockattr_destroy()
return zero. Otherwise, an error number is returned to indicate
the error (the
errno variable is not set).
ERRORS
For each of the following conditions, if the condition is detected, the pthread_rwlockattr_init()
and pthread_rwlockattr_destroy() functions return the corresponding error number:
[ENOMEM] There is insufficient memory available in which to initialize attr.
[EINVAL] The value specified by attr is invalid.
AUTHOR
pthread_rwlockattr_init() and pthread_rwlockattr_destroy()
were developed by
X/Open.
SEE ALSO
pthread_create(3T), pthread_rwlockattr_getpshared(3T), pthread_rwlockattr_setpshared(3T),
pthread_rwlock_init(3T).
STANDARDS CONFORMANCE
pthread_rwlockattr_init():X/Open.
pthread_rwlockattr_destroy():X/Open.
Section 3−−754 Hewlett-Packard Company − 1 − HP-UX 11i Version 1: September 2005