USLEEP(3) Library Functions Manual USLEEP(3)
usleep -- suspend execution for interval of microseconds
Standard C Library (libc, -lc)
The usleep() function suspends execution of the calling process until
either the number of microseconds specified by microseconds have elapsed
or a signal is delivered to the calling process and its action is to
invoke a signal catching function or to terminate the process. The
suspension time may be longer than requested due to the scheduling of
other activity by the system.
The microseconds argument must be less than 1,000,000. If the value of
microseconds is 0, then the call has no effect.
On successful completion, usleep() returns 0. Otherwise, it returns -1
and sets errno to indicate the error.
The usleep() function may fail if:
[EINVAL] The microseconds interval specified 1,000,000 or more
The usleep() function conforms to X/Open Portability Guide Issue 4,
Version 2 (``XPG4.2''). It later appeared in the POSIX standard, but in
IEEE Std 1003.1-2004 (``POSIX.1'') it was marked as legacy and the use of
nanosleep(2) was recommended instead. The IEEE Std 1003.1-2008
(``POSIX.1'') revision removed usleep() from the specification.
The usleep() function appeared in 4.3BSD.
NetBSD 6.1.5 April 29, 2010 NetBSD 6.1.5