high resolution sleep
struct timespec *timeout,
suspends execution of the calling process for the duration specified by
timeout. An unmasked signal will cause it to terminate
the sleep early, regardless of the
on the interrupting signal.
nanosleep() function returns
because the requested duration has elapsed, the value returned will be
nanosleep() function returns due to
the delivery of a signal, the value returned will be -1, and the global
variable errno will be set to indicate the
interruption. If remainder is non-null, the timespec
structure it references is updated to contain the unslept amount (the
requested duration minus the duration actually slept).
If any of the following conditions occur, the
nanosleep() function shall return -1 and set
errno to the corresponding value.
nanosleep() was interrupted by the delivery of a signal.
- timeout specified a nanosecond value less than zero or greater than or equal to 1000 million, or a second value less than zero.
- Either timeout or remainder points to memory that is not a valid part of the process address space.
nanosleep() function conforms to
IEEE Std 1003.1-2008 (“POSIX.1”).
The predecessor of this system call,
sleep(), appeared in
Version 3 AT&T UNIX, but was removed when
alarm(3) was introduced into Version 7
AT&T UNIX. The
nanosleep() system call
has been available since NetBSD 1.3 and was ported
to OpenBSD 2.1 and FreeBSD