1*fdd8201dSApple OSS Distributions /* 2*fdd8201dSApple OSS Distributions * Copyright (c) 2016 Apple Inc. All rights reserved. 3*fdd8201dSApple OSS Distributions * 4*fdd8201dSApple OSS Distributions * @APPLE_LICENSE_HEADER_START@ 5*fdd8201dSApple OSS Distributions * 6*fdd8201dSApple OSS Distributions * This file contains Original Code and/or Modifications of Original Code 7*fdd8201dSApple OSS Distributions * as defined in and that are subject to the Apple Public Source License 8*fdd8201dSApple OSS Distributions * Version 2.0 (the 'License'). You may not use this file except in 9*fdd8201dSApple OSS Distributions * compliance with the License. Please obtain a copy of the License at 10*fdd8201dSApple OSS Distributions * http://www.opensource.apple.com/apsl/ and read it before using this 11*fdd8201dSApple OSS Distributions * file. 12*fdd8201dSApple OSS Distributions * 13*fdd8201dSApple OSS Distributions * The Original Code and all software distributed under the License are 14*fdd8201dSApple OSS Distributions * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15*fdd8201dSApple OSS Distributions * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16*fdd8201dSApple OSS Distributions * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17*fdd8201dSApple OSS Distributions * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18*fdd8201dSApple OSS Distributions * Please see the License for the specific language governing rights and 19*fdd8201dSApple OSS Distributions * limitations under the License. 20*fdd8201dSApple OSS Distributions * 21*fdd8201dSApple OSS Distributions * @APPLE_LICENSE_HEADER_END@ 22*fdd8201dSApple OSS Distributions */ 23*fdd8201dSApple OSS Distributions #include <mach/mach_time.h> 24*fdd8201dSApple OSS Distributions 25*fdd8201dSApple OSS Distributions extern kern_return_t 26*fdd8201dSApple OSS Distributions mach_timebase_info_trap(mach_timebase_info_t info); 27*fdd8201dSApple OSS Distributions 28*fdd8201dSApple OSS Distributions kern_return_t mach_timebase_info(mach_timebase_info_t info)29*fdd8201dSApple OSS Distributionsmach_timebase_info(mach_timebase_info_t info) 30*fdd8201dSApple OSS Distributions { 31*fdd8201dSApple OSS Distributions static mach_timebase_info_data_t cached_info; 32*fdd8201dSApple OSS Distributions 33*fdd8201dSApple OSS Distributions /* 34*fdd8201dSApple OSS Distributions * This is racy, but because it is safe to initialize twice we avoid a 35*fdd8201dSApple OSS Distributions * barrier in the fast path by risking double initialization. 36*fdd8201dSApple OSS Distributions */ 37*fdd8201dSApple OSS Distributions if (cached_info.numer == 0 || cached_info.denom == 0) { 38*fdd8201dSApple OSS Distributions kern_return_t kr = mach_timebase_info_trap(&cached_info); 39*fdd8201dSApple OSS Distributions if (kr != KERN_SUCCESS) { 40*fdd8201dSApple OSS Distributions return kr; 41*fdd8201dSApple OSS Distributions } 42*fdd8201dSApple OSS Distributions } 43*fdd8201dSApple OSS Distributions 44*fdd8201dSApple OSS Distributions info->numer = cached_info.numer; 45*fdd8201dSApple OSS Distributions info->denom = cached_info.denom; 46*fdd8201dSApple OSS Distributions 47*fdd8201dSApple OSS Distributions return KERN_SUCCESS; 48*fdd8201dSApple OSS Distributions } 49