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usleep - Suspends execution for an interval of time
Standard C Library (libc.so, libc.a)
#include <unistd.h>
int usleep(
useconds_t useconds);
The following function declaration does not conform to current standards and is supported only for backward compatibility:
#include <unistd.h>
void usleep(
unsigned useconds);
Interfaces documented on this reference page conform to industry standards as follows:
usleep(): XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
Specifies the number of microseconds to sleep.
The usleep() function suspends the current process from execution for the number of microseconds specified by the useconds parameter. Because of other activity in the system, or because of the time spent in processing the call, the actual suspension time might be longer than specified.
The useconds parameter must be less than 1,000,000. If the value of useconds is 0 (zero), the usleep() function has no effect.
In a multithreaded environment, the sleep() function is redefined to suspend the calling thread.
On successful completion, the usleep() function returns 0 (zero). Otherwise, it returns -1 and sets errno to indicate the error.
The usleep() function sets errno to the specified values for the following conditions: The interval specified in the useconds parameter exceeds 1,000,000 microseconds.
Functions: getitimer(2), sigaction(2), sigvec(2), alarm(3), sleep(3)
Standards: standards(5) delim off