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RetroArch/deps/pthreads/pthread_mutexattr.c
twinaphex 9488e4e25a Add pthreads-emb implementation
2017-12-26 20:52:03 +01:00

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/*
* pthread_mutexattr.c
*
* Description:
* This translation unit implements mutual exclusion (mutex) primitives.
*
* --------------------------------------------------------------------------
*
* Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
* Copyright(C) 2008 Jason Schmidlapp
*
* Contact Email: jschmidlapp@users.sourceforge.net
*
*
* Based upon Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2005 Pthreads-win32 contributors
*
* Contact Email: rpj@callisto.canberra.edu.au
*
* The original list of contributors to the Pthreads-win32 project
* is contained in the file CONTRIBUTORS.ptw32 included with the
* source code distribution. The list can also be seen at the
* following World Wide Web location:
* http://sources.redhat.com/pthreads-win32/contributors.html
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library in the file COPYING.LIB;
* if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <stdlib.h>
#include "pthread.h"
#include "implement.h"
int pthread_mutexattr_destroy (pthread_mutexattr_t * attr)
/*
* ------------------------------------------------------
* DOCPUBLIC
* Destroys a mutex attributes object. The object can
* no longer be used.
*
* PARAMETERS
* attr
* pointer to an instance of pthread_mutexattr_t
*
*
* DESCRIPTION
* Destroys a mutex attributes object. The object can
* no longer be used.
*
* NOTES:
* 1) Does not affect mutexes created using 'attr'
*
* RESULTS
* 0 successfully released attr,
* EINVAL 'attr' is invalid.
*
* ------------------------------------------------------
*/
{
int result = 0;
if (attr == NULL || *attr == NULL)
result = EINVAL;
else
{
pthread_mutexattr_t ma = *attr;
*attr = NULL;
free (ma);
}
return (result);
}
int pthread_mutexattr_getkind_np (pthread_mutexattr_t * attr, int *kind)
{
return pthread_mutexattr_gettype (attr, kind);
}
int pthread_mutexattr_gettype (pthread_mutexattr_t * attr, int *kind)
{
int result = 0;
if (attr != NULL && *attr != NULL && kind != NULL)
*kind = (*attr)->kind;
else
result = EINVAL;
return (result);
}
int pthread_mutexattr_getpshared (const pthread_mutexattr_t * attr, int *pshared)
/*
* ------------------------------------------------------
* DOCPUBLIC
* Determine whether mutexes created with 'attr' can be
* shared between processes.
*
* PARAMETERS
* attr
* pointer to an instance of pthread_mutexattr_t
*
* pshared
* will be set to one of:
*
* PTHREAD_PROCESS_SHARED
* May be shared if in shared memory
*
* PTHREAD_PROCESS_PRIVATE
* Cannot be shared.
*
*
* DESCRIPTION
* Mutexes creatd with 'attr' can be shared between
* processes if pthread_mutex_t variable is allocated
* in memory shared by these processes.
* NOTES:
* 1) pshared mutexes MUST be allocated in shared
* memory.
* 2) The following macro is defined if shared mutexes
* are supported:
* _POSIX_THREAD_PROCESS_SHARED
*
* RESULTS
* 0 successfully retrieved attribute,
* EINVAL 'attr' is invalid,
*
* ------------------------------------------------------
*/
{
int result;
if ((attr != NULL && *attr != NULL) && (pshared != NULL))
{
*pshared = (*attr)->pshared;
result = 0;
}
else
result = EINVAL;
return (result);
}
int pthread_mutexattr_init (pthread_mutexattr_t * attr)
/*
* ------------------------------------------------------
* DOCPUBLIC
* Initializes a mutex attributes object with default
* attributes.
*
* PARAMETERS
* attr
* pointer to an instance of pthread_mutexattr_t
*
*
* DESCRIPTION
* Initializes a mutex attributes object with default
* attributes.
*
* NOTES:
* 1) Used to define mutex types
*
* RESULTS
* 0 successfully initialized attr,
* ENOMEM insufficient memory for attr.
*
* ------------------------------------------------------
*/
{
int result = 0;
pthread_mutexattr_t ma = (pthread_mutexattr_t) calloc (1, sizeof (*ma));
if (ma == NULL)
result = ENOMEM;
else
{
ma->pshared = PTHREAD_PROCESS_PRIVATE;
ma->kind = PTHREAD_MUTEX_DEFAULT;
}
*attr = ma;
return (result);
}
int pthread_mutexattr_setkind_np (pthread_mutexattr_t * attr, int kind)
{
return pthread_mutexattr_settype (attr, kind);
}
int pthread_mutexattr_setpshared (pthread_mutexattr_t * attr, int pshared)
/*
* ------------------------------------------------------
* DOCPUBLIC
* Mutexes created with 'attr' can be shared between
* processes if pthread_mutex_t variable is allocated
* in memory shared by these processes.
*
* PARAMETERS
* attr
* pointer to an instance of pthread_mutexattr_t
*
* pshared
* must be one of:
*
* PTHREAD_PROCESS_SHARED
* May be shared if in shared memory
*
* PTHREAD_PROCESS_PRIVATE
* Cannot be shared.
*
* DESCRIPTION
* Mutexes creatd with 'attr' can be shared between
* processes if pthread_mutex_t variable is allocated
* in memory shared by these processes.
*
* NOTES:
* 1) pshared mutexes MUST be allocated in shared
* memory.
*
* 2) The following macro is defined if shared mutexes
* are supported:
* _POSIX_THREAD_PROCESS_SHARED
*
* RESULTS
* 0 successfully set attribute,
* EINVAL 'attr' or pshared is invalid,
* ENOSYS PTHREAD_PROCESS_SHARED not supported,
*
* ------------------------------------------------------
*/
{
int result;
if ((attr != NULL && *attr != NULL) &&
((pshared == PTHREAD_PROCESS_SHARED) ||
(pshared == PTHREAD_PROCESS_PRIVATE)))
{
if (pshared == PTHREAD_PROCESS_SHARED)
{
#if !defined( _POSIX_THREAD_PROCESS_SHARED )
result = ENOSYS;
pshared = PTHREAD_PROCESS_PRIVATE;
#else
result = 0;
#endif /* _POSIX_THREAD_PROCESS_SHARED */
}
else
result = 0;
(*attr)->pshared = pshared;
}
else
result = EINVAL;
return (result);
}
int pthread_mutexattr_settype (pthread_mutexattr_t * attr, int kind)
/*
* ------------------------------------------------------
*
* DOCPUBLIC
* The pthread_mutexattr_settype() and
* pthread_mutexattr_gettype() functions respectively set and
* get the mutex type attribute. This attribute is set in the
* type parameter to these functions.
*
* PARAMETERS
* attr
* pointer to an instance of pthread_mutexattr_t
*
* type
* must be one of:
*
* PTHREAD_MUTEX_DEFAULT
*
* PTHREAD_MUTEX_NORMAL
*
* PTHREAD_MUTEX_ERRORCHECK
*
* PTHREAD_MUTEX_RECURSIVE
*
* DESCRIPTION
* The pthread_mutexattr_settype() and
* pthread_mutexattr_gettype() functions respectively set and
* get the mutex type attribute. This attribute is set in the
* type parameter to these functions. The default value of the
* type attribute is PTHREAD_MUTEX_DEFAULT.
*
* The type of mutex is contained in the type attribute of the
* mutex attributes. Valid mutex types include:
*
* PTHREAD_MUTEX_NORMAL
* This type of mutex does not detect deadlock. A
* thread attempting to relock this mutex without
* first unlocking it will deadlock. Attempting to
* unlock a mutex locked by a different thread
* results in undefined behavior. Attempting to
* unlock an unlocked mutex results in undefined
* behavior.
*
* PTHREAD_MUTEX_ERRORCHECK
* This type of mutex provides error checking. A
* thread attempting to relock this mutex without
* first unlocking it will return with an error. A
* thread attempting to unlock a mutex which another
* thread has locked will return with an error. A
* thread attempting to unlock an unlocked mutex will
* return with an error.
*
* PTHREAD_MUTEX_DEFAULT
* Same as PTHREAD_MUTEX_NORMAL.
*
* PTHREAD_MUTEX_RECURSIVE
* A thread attempting to relock this mutex without
* first unlocking it will succeed in locking the
* mutex. The relocking deadlock which can occur with
* mutexes of type PTHREAD_MUTEX_NORMAL cannot occur
* with this type of mutex. Multiple locks of this
* mutex require the same number of unlocks to
* release the mutex before another thread can
* acquire the mutex. A thread attempting to unlock a
* mutex which another thread has locked will return
* with an error. A thread attempting to unlock an
* unlocked mutex will return with an error. This
* type of mutex is only supported for mutexes whose
* process shared attribute is
* PTHREAD_PROCESS_PRIVATE.
*
* RESULTS
* 0 successfully set attribute,
* EINVAL 'attr' or 'type' is invalid,
*
* ------------------------------------------------------
*/
{
int result = 0;
if ((attr != NULL && *attr != NULL))
{
switch (kind)
{
case PTHREAD_MUTEX_FAST_NP:
case PTHREAD_MUTEX_RECURSIVE_NP:
case PTHREAD_MUTEX_ERRORCHECK_NP:
(*attr)->kind = kind;
break;
default:
result = EINVAL;
break;
}
}
else
result = EINVAL;
return (result);
}
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