mirror of
https://git.rtems.org/rtems-docs/
synced 2025-05-17 13:14:40 +08:00
321 lines
6.9 KiB
ReStructuredText
321 lines
6.9 KiB
ReStructuredText
Condition Variable Manager
|
|
##########################
|
|
|
|
Introduction
|
|
============
|
|
|
|
The condition variable manager ...
|
|
|
|
The directives provided by the condition variable manager are:
|
|
|
|
- ``pthread_condattr_init`` - Initialize a Condition Variable Attribute Set
|
|
|
|
- ``pthread_condattr_destroy`` - Destroy a Condition Variable Attribute Set
|
|
|
|
- ``pthread_condattr_setpshared`` - Set Process Shared Attribute
|
|
|
|
- ``pthread_condattr_getpshared`` - Get Process Shared Attribute
|
|
|
|
- ``pthread_cond_init`` - Initialize a Condition Variable
|
|
|
|
- ``pthread_cond_destroy`` - Destroy a Condition Variable
|
|
|
|
- ``pthread_cond_signal`` - Signal a Condition Variable
|
|
|
|
- ``pthread_cond_broadcast`` - Broadcast a Condition Variable
|
|
|
|
- ``pthread_cond_wait`` - Wait on a Condition Variable
|
|
|
|
- ``pthread_cond_timedwait`` - With with Timeout a Condition Variable
|
|
|
|
Background
|
|
==========
|
|
|
|
There is currently no text in this section.
|
|
|
|
Operations
|
|
==========
|
|
|
|
There is currently no text in this section.
|
|
|
|
Directives
|
|
==========
|
|
|
|
This section details the condition variable manager's directives.
|
|
A subsection is dedicated to each of this manager's directives
|
|
and describes the calling sequence, related constants, usage,
|
|
and status codes.
|
|
|
|
pthread_condattr_init - Initialize a Condition Variable Attribute Set
|
|
---------------------------------------------------------------------
|
|
.. index:: pthread_condattr_init
|
|
.. index:: initialize a condition variable attribute set
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_condattr_init(
|
|
pthread_condattr_t \*attr
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*ENOMEM*
|
|
Insufficient memory is available to initialize the condition variable
|
|
attributes object.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_condattr_destroy - Destroy a Condition Variable Attribute Set
|
|
---------------------------------------------------------------------
|
|
.. index:: pthread_condattr_destroy
|
|
.. index:: destroy a condition variable attribute set
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_condattr_destroy(
|
|
pthread_condattr_t \*attr
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
The attribute object specified is invalid.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_condattr_setpshared - Set Process Shared Attribute
|
|
----------------------------------------------------------
|
|
.. index:: pthread_condattr_setpshared
|
|
.. index:: set process shared attribute
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_condattr_setpshared(
|
|
pthread_condattr_t \*attr,
|
|
int pshared
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
Invalid argument passed.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_condattr_getpshared - Get Process Shared Attribute
|
|
----------------------------------------------------------
|
|
.. index:: pthread_condattr_getpshared
|
|
.. index:: get process shared attribute
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_condattr_getpshared(
|
|
const pthread_condattr_t \*attr,
|
|
int \*pshared
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
Invalid argument passed.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_cond_init - Initialize a Condition Variable
|
|
---------------------------------------------------
|
|
.. index:: pthread_cond_init
|
|
.. index:: initialize a condition variable
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_cond_init(
|
|
pthread_cond_t \*cond,
|
|
const pthread_condattr_t \*attr
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EAGAIN*
|
|
The system lacked a resource other than memory necessary to create the
|
|
initialize the condition variable object.
|
|
|
|
*ENOMEM*
|
|
Insufficient memory is available to initialize the condition variable object.
|
|
|
|
*EBUSY*
|
|
The specified condition variable has already been initialized.
|
|
|
|
*EINVAL*
|
|
The specified attribute value is invalid.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_cond_destroy - Destroy a Condition Variable
|
|
---------------------------------------------------
|
|
.. index:: pthread_cond_destroy
|
|
.. index:: destroy a condition variable
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_cond_destroy(
|
|
pthread_cond_t \*cond
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
The specified condition variable is invalid.
|
|
|
|
*EBUSY*
|
|
The specified condition variable is currently in use.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_cond_signal - Signal a Condition Variable
|
|
-------------------------------------------------
|
|
.. index:: pthread_cond_signal
|
|
.. index:: signal a condition variable
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_cond_signal(
|
|
pthread_cond_t \*cond
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
The specified condition variable is not valid.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
This routine should not be invoked from a handler from an asynchronous signal
|
|
handler or an interrupt service routine.
|
|
|
|
pthread_cond_broadcast - Broadcast a Condition Variable
|
|
-------------------------------------------------------
|
|
.. index:: pthread_cond_broadcast
|
|
.. index:: broadcast a condition variable
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_cond_broadcast(
|
|
pthread_cond_t \*cond
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
The specified condition variable is not valid.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
This routine should not be invoked from a handler from an asynchronous signal
|
|
handler or an interrupt service routine.
|
|
|
|
pthread_cond_wait - Wait on a Condition Variable
|
|
------------------------------------------------
|
|
.. index:: pthread_cond_wait
|
|
.. index:: wait on a condition variable
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_cond_wait(
|
|
pthread_cond_t \*cond,
|
|
pthread_mutex_t \*mutex
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
The specified condition variable or mutex is not initialized OR different
|
|
mutexes were specified for concurrent pthread_cond_wait() and
|
|
pthread_cond_timedwait() operations on the same condition variable OR
|
|
the mutex was not owned by the current thread at the time of the call.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
pthread_cond_timedwait - Wait with Timeout a Condition Variable
|
|
---------------------------------------------------------------
|
|
.. index:: pthread_cond_timedwait
|
|
.. index:: wait with timeout a condition variable
|
|
|
|
**CALLING SEQUENCE:**
|
|
|
|
.. code:: c
|
|
|
|
#include <pthread.h>
|
|
int pthread_cond_timedwait(
|
|
pthread_cond_t \*cond,
|
|
pthread_mutex_t \*mutex,
|
|
const struct timespec \*abstime
|
|
);
|
|
|
|
**STATUS CODES:**
|
|
|
|
*EINVAL*
|
|
The specified condition variable or mutex is not initialized OR different
|
|
mutexes were specified for concurrent pthread_cond_wait() and
|
|
pthread_cond_timedwait() operations on the same condition variable OR
|
|
the mutex was not owned by the current thread at the time of the call.
|
|
|
|
*ETIMEDOUT*
|
|
The specified time has elapsed without the condition variable being
|
|
satisfied.
|
|
|
|
**DESCRIPTION:**
|
|
|
|
**NOTES:**
|
|
|
|
.. COMMENT: COPYRIGHT (c) 1988-2002.
|
|
|
|
.. COMMENT: On-Line Applications Research Corporation (OAR).
|
|
|
|
.. COMMENT: All rights reserved.
|
|
|