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usleep(3) Library Functions Manual usleep(3) NAME usleep - Suspends execution for an interval of time LIBRARY Standard C Library (libc.so, libc.a) SYNOPSIS #include <unistd.h> int usleep( useconds_t useconds); The following function declaration does not conform to current stan- dards and is supported only for backward compatibility: #include <unistd.h> void usleep( unsigned useconds); STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: usleep(): XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. PARAMETERS Specifies the number of microseconds to sleep. DESCRIPTION The usleep() function suspends the current process from execution for the number of microseconds specified by the useconds parameter. Be- cause 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. RETURN VALUES On successful completion, the usleep() function returns 0 (zero). Oth- erwise, it returns -1 and sets errno to indicate the error. ERRORS The usleep() function sets errno to the specified values for the fol- lowing conditions: The interval specified in the useconds parameter ex- ceeds 1,000,000 microseconds. RELATED INFORMATION Functions: getitimer(2), sigaction(2), sigvec(2), alarm(3), sleep(3) Standards: standards(5) delim off usleep(3)