Unix/Linux Go Back    


Linux 2.6 - man page for pthread_mutexattr_setprotocol (linux section 3posix)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


PTHREAD_MUTEXATTR_GETPROTOCOL(P)    POSIX Programmer's Manual	 PTHREAD_MUTEXATTR_GETPROTOCOL(P)

NAME
       pthread_mutexattr_getprotocol,  pthread_mutexattr_setprotocol  -  get and set the protocol
       attribute of the mutex attributes object (REALTIME THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *
	      restrict attr, int *restrict protocol);
       int pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr,
	      int protocol);

DESCRIPTION
       The pthread_mutexattr_getprotocol() and pthread_mutexattr_setprotocol() functions, respec-
       tively,	shall  get and set the protocol attribute of a mutex attributes object pointed to
       by attr which was previously created by the function pthread_mutexattr_init().

       The protocol attribute defines the protocol to be followed in utilizing mutexes. The value
       of protocol may be one of:

       PTHREAD_PRIO_NONE

       PTHREAD_PRIO_INHERIT

       PTHREAD_PRIO_PROTECT

       which are defined in the <pthread.h> header.

       When a thread owns a mutex with the PTHREAD_PRIO_NONE protocol attribute, its priority and
       scheduling shall not be affected by its mutex ownership.

       When a thread is blocking higher priority threads because of owning one	or  more  mutexes
       with  the  PTHREAD_PRIO_INHERIT	protocol attribute, it shall execute at the higher of its
       priority or the priority of the highest priority thread waiting	on  any  of  the  mutexes
       owned by this thread and initialized with this protocol.

       When a thread owns one or more mutexes initialized with the PTHREAD_PRIO_PROTECT protocol,
       it shall execute at the higher of its priority or the highest of the priority ceilings  of
       all  the  mutexes  owned by this thread and initialized with this attribute, regardless of
       whether other threads are blocked on any of these mutexes or not.

       While a thread is holding a mutex which has been initialized with the PTHREAD_PRIO_INHERIT
       or PTHREAD_PRIO_PROTECT protocol attributes, it shall not be subject to being moved to the
       tail of the scheduling queue at its priority in the event that its  original  priority  is
       changed,  such  as by a call to sched_setparam().  Likewise, when a thread unlocks a mutex
       that has been initialized with the PTHREAD_PRIO_INHERIT or  PTHREAD_PRIO_PROTECT  protocol
       attributes,  it shall not be subject to being moved to the tail of the scheduling queue at
       its priority in the event that its original priority is changed.

       If a thread simultaneously owns several mutexes initialized with different  protocols,  it
       shall  execute  at  the	highest  of the priorities that it would have obtained by each of
       these protocols.

       When a thread makes a call to pthread_mutex_lock(), the mutex  was  initialized	with  the
       protocol  attribute  having  the  value	PTHREAD_PRIO_INHERIT,  when the calling thread is
       blocked because the mutex is owned by another thread, that owner thread shall inherit  the
       priority  level of the calling thread as long as it continues to own the mutex. The imple-
       mentation shall update its execution priority to the maximum of its assigned priority  and
       all  its inherited priorities. Furthermore, if this owner thread itself becomes blocked on
       another mutex, the same priority inheritance effect shall  be  propagated  to  this  other
       owner thread, in a recursive manner.

RETURN VALUE
       Upon successful completion, the pthread_mutexattr_getprotocol() and pthread_mutexattr_set-
       protocol() functions shall return zero; otherwise, an error number shall  be  returned  to
       indicate the error.

ERRORS
       The pthread_mutexattr_setprotocol() function shall fail if:

       ENOTSUP
	      The value specified by protocol is an unsupported value.

       The pthread_mutexattr_getprotocol() and pthread_mutexattr_setprotocol() functions may fail
       if:

       EINVAL The value specified by attr or protocol is invalid.

       EPERM  The caller does not have the privilege to perform the operation.

       These functions shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_cond_destroy() , pthread_create() , pthread_mutex_destroy() , the Base Definitions
       volume of IEEE Std 1003.1-2001, <pthread.h>

COPYRIGHT
       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable	Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003		 PTHREAD_MUTEXATTR_GETPROTOCOL(P)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 09:56 PM.