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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___SUPPORT_IBM_NANOSLEEP_H11#define _LIBCPP___SUPPORT_IBM_NANOSLEEP_H12 13#include <unistd.h>14 15inline int nanosleep(const struct timespec* __req, struct timespec* __rem) {16 // The nanosleep() function is not available on z/OS. Therefore, we will call17 // sleep() to sleep for whole seconds and usleep() to sleep for any remaining18 // fraction of a second. Any remaining nanoseconds will round up to the next19 // microsecond.20 if (__req->tv_sec < 0 || __req->tv_nsec < 0 || __req->tv_nsec > 999999999) {21 errno = EINVAL;22 return -1;23 }24 long __micro_sec = (__req->tv_nsec + 999) / 1000;25 time_t __sec = __req->tv_sec;26 if (__micro_sec > 999999) {27 ++__sec;28 __micro_sec -= 1000000;29 }30 __sec = static_cast<time_t>(sleep(static_cast<unsigned int>(__sec)));31 if (__sec) {32 if (__rem) {33 // Updating the remaining time to sleep in case of unsuccessful call to sleep().34 __rem->tv_sec = __sec;35 __rem->tv_nsec = __micro_sec * 1000;36 }37 errno = EINTR;38 return -1;39 }40 if (__micro_sec) {41 int __rt = usleep(static_cast<unsigned int>(__micro_sec));42 if (__rt != 0 && __rem) {43 // The usleep() does not provide the amount of remaining time upon its failure,44 // so the time slept will be ignored.45 __rem->tv_sec = 0;46 __rem->tv_nsec = __micro_sec * 1000;47 // The errno is already set.48 return -1;49 }50 return __rt;51 }52 return 0;53}54 55#endif // _LIBCPP___SUPPORT_IBM_NANOSLEEP_H56