pthread_spin_init(3)

NAME

pthread_spin_init, pthread_spin_destroy - initialize or de

stroy a spin
lock

LIBRARY

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

SYNOPSIS

#include <pthread.h>
int
pthread_spin_init(pthread_spinlock_t *lock, int pshared);
int
pthread_spin_destroy(pthread_spinlock_t *lock);

DESCRIPTION

The pthread_spin_init() function will initialize lock to an

unlocked
state and allocate any resources necessary to begin using

it. If pshared
is set to PTHREAD_PROCESS_SHARED, any thread, whether be

longing to the
process in which the spinlock was created or not, that has

access to the
memory area where lock resides, can use lock. If it is set

to
PTHREAD_PROCESS_PRIVATE, it can only be used by threads

within the same
process.

The pthread_spin_destroy() function will destroy lock and

release any
resources that may have been allocated on its behalf.

RETURN VALUES

If successful, both pthread_spin_init() and

pthread_spin_destroy() will
return zero. Otherwise, an error number will be returned to

indicate the
error.

Neither of these functions will return EINTR.

ERRORS

The pthread_spin_init() and pthread_spin_destroy() functions

will fail
if:

[EBUSY] An attempt to initialize or destroy lock

while it is

in use.

[EINVAL] The value specified by lock is invalid.

The pthread_spin_init() function will fail if:

[EAGAIN] Insufficient resources, other than memo

ry, to initial

ize lock.

[ENOMEM] Insufficient memory to initialize lock.

SEE ALSO

pthread_spin_lock(3), pthread_spin_unlock(3)

HISTORY

The pthread_spin_init() and pthread_spin_destroy() functions

first
appeared in library ``libpthread'' in FreeBSD 5.2, and in

library
``libthr'' in FreeBSD 5.3.

BUGS

The implementation of pthread_spin_init() does not fully

conform to IEEE
Std 1003.2 (``POSIX.2'') because the pshared argument is ig

nored in
library ``libthr'', and in library ``libpthread'' if any

value other than
PTHREAD_PROCESSES_PRIVATE is specified, it returns EINVAL.

BSD January 22, 2004

BSD