netbsd man page for usleep

USLEEP(3)						   BSD Library Functions Manual 						 USLEEP(3)

NAME
     usleep -- suspend execution for interval of microseconds

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     int
     usleep(useconds_t microseconds);

DESCRIPTION
     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.

RETURN VALUES
     On successful completion, usleep() returns 0.  Otherwise, it returns -1 and sets errno to indicate the error.

ERRORS
     The usleep() function may fail if:

     [EINVAL]		The microseconds interval specified 1,000,000 or more microseconds.

SEE ALSO
     nanosleep(2), sleep(3)

STANDARDS
     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.

HISTORY
     The usleep() function appeared in 4.3BSD.

BSD
								  April 29, 2010							       BSD