The
usleep()
function suspends execution of the calling process for
(at least) usec microseconds.
The sleep may be lengthened slightly
by any system activity or by the time spent processing the call or by the
granularity of system timers.
usec is not smaller than 1000000.
(On systems where that is considered an error.)
CONFORMING TO
4.3BSD, POSIX.1-2001.
POSIX.1-2001 declares this function obsolete; use
nanosleep(2)
instead.
POSIX.1-2008 removes the specification of
usleep().
On the original BSD implementation,
and in glibc before version 2.2.2, the return type of this function is
void.
The POSIX version returns
int,
and this is also the prototype used since glibc 2.2.2.
Only the
EINVAL
error return is documented by SUSv2 and POSIX.1-2001.
NOTES
The type
useconds_t
is an unsigned integer type capable of holding integers
in the range [0,1000000].
Programs will be more portable
if they never mention this type explicitly.
Use
#include <unistd.h>
...
unsigned int usecs;
...
usleep(usecs);
This page is part of release 3.14 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/.
