NAME
sempost - unlock a semaphore SYNOPSIS
#include
int sempost(semt *sem); Link with -pthread. DESCRIPTION sempost() increments (unlocks) the semaphore pointed to by sem. If the semaphore's value consequently becomes greater than zero, then another process or thread blocked in a semwait(3) call will be woken up and proceed to lock the semaphore. RETURN VALUE sempost() returns 0 on success; on error, the value of the semaphore
is left unchanged, -1 is returned, and errno is set to indicate the error. ERRORS EINVAL sem is not a valid semaphore. EOVERFLOW The maximum allowable value for a semaphore would be exceeded. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌───────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├───────────┼───────────────┼─────────┤
│sempost() │ Thread safety │ MT-Safe │ └───────────┴───────────────┴─────────┘ CONFORMING TO
POSIX.1-2001. NOTES
sempost() is async-signal-safe: it may be safely called within a sig‐ nal handler. EXAMPLE See semwait(3). SEE ALSO semgetvalue(3), semwait(3), semoverview(7) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2012-05-13 SEMPOST(3)