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nanosleep — suspend process execution for an interval measured in nanoseconds
Standard C Library (libc, -lc)
#include <time.h> int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
The nanosleep() system call causes the calling thread to sleep until the time interval specified by rqtp has elapsed. An unmasked signal will cause it to terminate the sleep early, regardless of the SA_RESTART value on the interrupting signal.
If the nanosleep() system call returns because the requested time has elapsed, the value returned will be zero. If the nanosleep() system call 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 rmtp is non-NULL, the timespec structure it references is updated to contain the unslept amount (the request time minus the time actually slept).
The nanosleep() system call fails if: [EFAULT] Either rqtp or rmtp points to memory that is not a valid part of the process address space. [EINTR] The nanosleep() system call was interrupted by the delivery of a signal. [EINVAL] The rqtp argument specified a nanosecond value less than zero or greater than or equal to 1000 million. [ENOSYS] The nanosleep() system call is not supported by this implementation.
The nanosleep() system call conforms to IEEE Std 1003.1b-1993 (“POSIX.1”).