pthread_barrierattr(3)

NAME

pthread_barrierattr_destroy, pthread_barrierattr_getpshared, pthread_barrierattr_init, pthread_barrierattr_setpshared

manipulate a
barrier attribute object

LIBRARY

library ``libpthread'' library ``libthr''

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 at

tached 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 at

tached to may be

accessed by threads in process

es other than
the one that created the ob

ject.

RETURN VALUES

If successful, all these functions will return zero. Other

wise, 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 li

brary
``libpthread'' in FreeBSD 5.2, and in library ``libthr'' in

FreeBSD 5.3.

BUGS

The implementation of barriers does not fully conform to

IEEE Std 1003.2
(``POSIX.2'') because the process-shared attribute is ig

nored in library
``libthr'', and in library ``libpthread''; if any value oth

er than
PTHREAD_PROCESSES_PRIVATE is specified in a call to
pthread_barrierattr_setpshared(), it will return EINVAL.

BSD February 19, 2004

BSD