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PTHREAD_RWLOCK_TIMEDRDLOCK (3) | C library functions | Unix Manual Pages | :man

NAME

pthread_rwlock_timedrdlock - "acquire a read-write lock for reading or give up after a specified period"

CONTENTS

Library
Synopsis
Description
Implementation Notes
Return Values
Errors
See Also
Standards
History

LIBRARY


.Lb libpthread
.Lb libthr

SYNOPSIS


.In pthread.h int pthread_rwlock_timedrdlock "pthread_rwlock_t *rwlock" "const struct timespec *abs_timeout"

DESCRIPTION

This function acquires a read lock on the read-write lock rwlock. However, if the lock cannot be acquired without waiting for another thread to unlock the lock, this wait shall be terminated when abs_timeout expires.

A thread may hold multiple concurrent read locks. The pthread_rwlock_unlock(3) function must be called once for each lock acquired.

If the thread should be interrupted by a signal, the pthread_rwlock_timedrdlock function will be automatically restarted after the thread returns from the signal handler.

The calling thread may deadlock if at the time the call is made it holds a write lock on rwlock. The results are undefined if this function is called with an uninitialized read-write lock.

IMPLEMENTATION NOTES

To prevent writer starvation, writers are favored over readers.

RETURN VALUES

If successful, the pthread_rwlock_timedrdlock function will return zero. Otherwise, an error number will be returned to indicate the error.

This function shall not return an error code of EINTR.

ERRORS

The pthread_rwlock_timedrdlock function will fail if:
[ETIMEDOUT]
The lock could not be acquired before the specified timeout expired.

The pthread_rwlock_timedrdlock function may fail if:

[EAGAIN]
The read lock could not be acquired because the maximum number of read locks for rwlock would be exceeded.
[EDEADLK]
The calling thread already holds a write lock on rwlock.
[EINVAL]
The value specified by rwlock does not refer to an initialized read-write lock object, or the abs_timeout nanosecond value is less than zero or greater than or equal to 1 billion.

SEE ALSO

pthread_rwlock_init(3), pthread_rwlock_timedwrlock(3), pthread_rwlock_unlock(3)

STANDARDS

HISTORY


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