sem_trywait man page on FreeBSD

Man page or keyword search:  
man Server   9747 pages
apropos Keyword Search (all sections)
Output format
FreeBSD logo
[printable version]

SEM_WAIT(3)		 BSD Library Functions Manual		   SEM_WAIT(3)

NAME
     sem_wait, sem_trywait — decrement (lock) a semaphore

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <semaphore.h>

     int
     sem_wait(sem_t *sem);

     int
     sem_trywait(sem_t *sem);

DESCRIPTION
     The sem_wait() function decrements (locks) the semaphore pointed to by
     sem, but blocks if the value of sem is zero, until the value is non-zero
     and the value can be decremented.

     The sem_trywait() function decrements (locks) the semaphore pointed to by
     sem only if the value is non-zero.	 Otherwise, the semaphore is not
     decremented and an error is returned.

RETURN VALUES
     Upon successful completion, the value 0 is returned; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     The sem_wait() and sem_trywait() functions will fail if:

     [EINVAL]		The sem argument points to an invalid semaphore.

     Additionally, sem_trywait() will fail if:

     [EAGAIN]		The semaphore value was zero, and thus could not be
			decremented.

SEE ALSO
     sem_getvalue(3), sem_post(3), sem_timedwait(3), sem(4)

STANDARDS
     The sem_wait() and sem_trywait() functions conform to ISO/IEC 9945-1:1996
     (“POSIX.1”).

BSD			       February 15, 2000			   BSD
[top]

List of man pages available for FreeBSD

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
...................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net