usleep(3) [osx man page]
USLEEP(3) BSD Library Functions Manual USLEEP(3) NAME
usleep -- suspend thread execution for an interval measured in microseconds LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int usleep(useconds_t useconds); DESCRIPTION
The usleep() function suspends execution of the calling thread until either useconds microseconds have elapsed or a signal is delivered to the thread whose action is to invoke a signal-catching function or to terminate the thread or process. The actual time slept may be longer, due to system latencies and possible limitations in the timer resolution of the hardware. This function is implemented, using nanosleep(2), by pausing for useconds microseconds or until a signal occurs. Consequently, in this implementation, sleeping has no effect on the state of process timers and there is no special handling for SIGALRM. RETURN VALUES
The usleep() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
The usleep() function will fail if: [EINTR] A signal was delivered to the process and its action was to invoke a signal-catching function. SEE ALSO
nanosleep(2), sleep(3) HISTORY
The usleep() function appeared in 4.3BSD. BSD
February 13, 1998 BSD
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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