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PTHREAD_CONDATTR(3)   DragonFly Library Functions Manual   PTHREAD_CONDATTR(3)


NAME

     pthread_condattr_init, pthread_condattr_destroy,
     pthread_condattr_getclock, pthread_condattr_setclock,
     pthread_condattr_getpshared, pthread_condattr_setpshared -- condition
     attribute operations


LIBRARY

     POSIX Threads Library (libpthread, -lpthread)


SYNOPSIS

     #include <pthread.h>

     int
     pthread_condattr_init(pthread_condattr_t *attr);

     int
     pthread_condattr_destroy(pthread_condattr_t *attr);

     int
     pthread_condattr_getclock(const pthread_condattr_t * restrict attr,
         clockid_t * restrict clock_id);

     int
     pthread_condattr_setclock(pthread_condattr_t *attr, clockid_t clock_id);

     int
     pthread_condattr_getpshared(const pthread_condattr_t * restrict attr,
         int * restrict pshared);

     int
     pthread_condattr_setpshared(pthread_condattr_t *attr, int pshared);


DESCRIPTION

     Condition attribute objects are used to specify parameters to
     pthread_cond_init().  DragonFly's implementation of conditions does not
     support any non-default attributes, so these functions are not very
     useful, though they are required to be present by POSIX.

     The pthread_condattr_init() function initializes a condition attribute
     object with the default attributes.

     The pthread_condattr_destroy() function destroys a condition attribute
     object.

     The pthread_condattr_getclock() function will put the value of the clock
     attribute from attr into the memory area pointed to by clock_id.  The
     pthread_condattr_setclock() function will set the clock attribute of attr
     to the value specified in clock_id.  The clock attribute affects the
     interpretation of abstime in pthread_cond_timedwait(3) and may be set to
     CLOCK_REALTIME (default) or CLOCK_MONOTONIC.

     The pthread_condattr_getpshared() function will put the value of the
     process-shared attribute from attr into the memory area pointed to by
     pshared.  The pthread_condattr_setpshared() function will set the
     process-shared attribute of attr to the value specified in pshared.  The
     argument pshared may have the following value:

     PTHREAD_PROCESS_PRIVATE  The condition variable it is attached to may
                              only be accessed by threads in the same process
                              as the one that created the object.


RETURN VALUES

     If successful, these functions return 0.  Otherwise, an error number is
     returned to indicate the error.


ERRORS

     The pthread_condattr_init() function will fail if:

     [ENOMEM]           Out of memory.

     The pthread_condattr_destroy() function will fail if:

     [EINVAL]           Invalid value for attr.

     The pthread_condattr_setclock() function will fail if:

     [EINVAL]           The value specified in clock_id is not one of the
                        allowed values.

     The pthread_condattr_setpshared() function will fail if:

     [EINVAL]           The value specified in pshared is not one of the
                        allowed values.


SEE ALSO

     pthread_cond_init(3), pthread_cond_timedwait(3)


STANDARDS

     The pthread_condattr_init() and pthread_condattr_destroy() functions
     conform to ISO/IEC 9945-1:1996 (``POSIX.1'').

DragonFly 4.9                  November 30, 2017                 DragonFly 4.9

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