PTHREAD_BARRIERATTR(3)

NAME
pthread_barrierattr_destroy, pthread_barrierattr_getpshared, pthread_barrierattr_init, pthread_barrierattr_setpshared - manipulate a barrier attribute object

LIBRARY
libpthread

SYNOPSIS
#include <pthread.h>
int
pthread_barrierattr_destroy(pthread_barrierattr_t *attr);
int
pthread_barrierattr_getpshared(const pthread_barrierattr_t *attr, int *pshared);
int
pthread_barrierattr_init(pthread_barrierattr_t *attr);
int
pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int pshared);

DESCRIPTION
The pthread_barrierattr_init() function will initialize attr with default attributes. The pthread_barrierattr_destroy() function will destroy attr and release any resources that may have been allocated on its behalf.

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

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

PTHREAD_PROCESS_SHARED
    The barrier object it is attached to may be accessed by threads in processes other than the one that created the object.

RETURN VALUES
If successful, all these functions will return zero. Otherwise, an error number will be returned to indicate the error.

None of these functions will return EINTR.

ERRORS
The pthread_barrierattr_destroy(), pthread_barrierattr_getpshared() and pthread_barrierattr_setpshared() functions may fail if:

[EINVAL]
    The value specified by attr is invalid.

The pthread_barrierattr_init() function will fail if:

[ENOMEM]
    Insufficient memory to initialize the barrier attribute object attr.

The pthread_barrierattr_setpshared() function will fail if:

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

SEE ALSO
pthread_barrier_destroy(3), pthread_barrier_init(3), pthread_barrier_wait(3)

HISTORY
The pthread_barrierattr_*() functions first appeared in libkse in FreeBSD 5.2, and in libthr in FreeBSD 5.3.

BUGS
The implementation of barriers does not fully conform to p1003.2 because the process-shared attribute is ignored in libthr, and in libkse; if any value other than PTHREAD_PROCESSES_PRIVATE is specified in a call to pthread_barrierattr_setpshared(), it will return EINVAL.