# pthread_attr_getschedpolicy

## PROLOG



           This manual page is part of the POSIX Programmer's Manual.  The
           Linux implementation of this interface may differ (consult the
           corresponding Linux manual page for details of Linux behavior), or
           the interface may not be implemented on Linux.
    


## NAME



           pthread_attr_getschedpolicy, pthread_attr_setschedpolicy — get and
           set the schedpolicy attribute (**REALTIME THREADS**)
    


## SYNOPSIS



           #include <pthread.h>
    
           int pthread_attr_getschedpolicy(const pthread_attr_t *restrict _attr_ ,
               int *restrict _policy_);
           int pthread_attr_setschedpolicy(pthread_attr_t *_attr_ , int _policy_);
    


## DESCRIPTION



           The _pthread_attr_getschedpolicy_() and
           _pthread_attr_setschedpolicy_() functions, respectively, shall get
           and set the _schedpolicy_ attribute in the _attr_ argument.
    
           The supported values of _policy_ shall include SCHED_FIFO, SCHED_RR,
           and SCHED_OTHER, which are defined in the _< sched.h>_ header. When
           threads executing with the scheduling policy SCHED_FIFO, SCHED_RR,
           or SCHED_SPORADIC are waiting on a mutex, they shall acquire the
           mutex in priority order when the mutex is unlocked.
    
           The behavior is undefined if the value specified by the _attr_
           argument to _pthread_attr_getschedpolicy_() or
           _pthread_attr_setschedpolicy_() does not refer to an initialized
           thread attributes object.
    


## RETURN VALUE



           If successful, the _pthread_attr_getschedpolicy_() and
           _pthread_attr_setschedpolicy_() functions shall return zero;
           otherwise, an error number shall be returned to indicate the
           error.
    


## ERRORS



           The _pthread_attr_setschedpolicy_() function shall fail if:
    
           **ENOTSUP**
                  An attempt was made to set the attribute to an unsupported
                  value.
    
           The _pthread_attr_setschedpolicy_() function may fail if:
    
           **EINVAL** The value of _policy_ is not valid.
    
           These functions shall not return an error code of **[EINTR]**.
    
           _The following sections are informative._
    


## EXAMPLES



           None.
    


## APPLICATION USAGE



           After these attributes have been set, a thread can be created with
           the specified attributes using _pthread_create_().  Using these
           routines does not affect the current running thread.
    
           See _Section 2.9.4_ , _Thread Scheduling_ for further details on thread
           scheduling attributes and their default settings.
    


## RATIONALE



           If an implementation detects that the value specified by the _attr_
           argument to _pthread_attr_getschedpolicy_() or
           _pthread_attr_setschedpolicy_() does not refer to an initialized
           thread attributes object, it is recommended that the function
           should fail and report an **[EINVAL]** error.
    


## FUTURE DIRECTIONS



           None.
    


* * *