dispatch/time.h

   1 /*
   2  * Copyright (c) 2008-2011 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 #ifndef __DISPATCH_TIME__
  22 #define __DISPATCH_TIME__
  23
  24 #ifndef __DISPATCH_INDIRECT__
  25 #error "Please #include <dispatch/dispatch.h> instead of this file directly."
  26 #include <dispatch/base.h> // for HeaderDoc
  27 #endif
  28
  29 #include <stdint.h>
  30
  31 // <rdar://problem/6368156&7563559>
  32 #if TARGET_OS_MAC
  33 #include <mach/clock_types.h>
  34 #endif
  35
  36 DISPATCH_ASSUME_NONNULL_BEGIN
  37
  38 #ifdef NSEC_PER_SEC
  39 #undef NSEC_PER_SEC
  40 #endif
  41 #ifdef USEC_PER_SEC
  42 #undef USEC_PER_SEC
  43 #endif
  44 #ifdef NSEC_PER_USEC
  45 #undef NSEC_PER_USEC
  46 #endif
  47 #ifdef NSEC_PER_MSEC
  48 #undef NSEC_PER_MSEC
  49 #endif
  50 #define NSEC_PER_SEC 1000000000ull
  51 #define NSEC_PER_MSEC 1000000ull
  52 #define USEC_PER_SEC 1000000ull
  53 #define NSEC_PER_USEC 1000ull
  54
  55 __BEGIN_DECLS
  56
  57 struct timespec;
  58
  59 /*!
  60  * @typedef dispatch_time_t
  61  *
  62  * @abstract
  63  * A somewhat abstract representation of time; where zero means "now" and
  64  * DISPATCH_TIME_FOREVER means "infinity" and every value in between is an
  65  * opaque encoding.
  66  */
  67 typedef uint64_t dispatch_time_t;
  68
  69 #define DISPATCH_TIME_NOW (0ull)
  70 #define DISPATCH_TIME_FOREVER (~0ull)
  71
  72 /*!
  73  * @function dispatch_time
  74  *
  75  * @abstract
  76  * Create dispatch_time_t relative to the default clock or modify an existing
  77  * dispatch_time_t.
  78  *
  79  * @discussion
  80  * On Mac OS X the default clock is based on mach_absolute_time().
  81  *
  82  * @param when
  83  * An optional dispatch_time_t to add nanoseconds to. If zero is passed, then
  84  * dispatch_time() will use the result of mach_absolute_time().
  85  *
  86  * @param delta
  87  * Nanoseconds to add.
  88  *
  89  * @result
  90  * A new dispatch_time_t.
  91  */
  92 API_AVAILABLE(macos(10.6), ios(4.0))
  93 DISPATCH_EXPORT DISPATCH_WARN_RESULT DISPATCH_NOTHROW
  94 dispatch_time_t
  95 dispatch_time(dispatch_time_t when, int64_t delta);
  96
  97 /*!
  98  * @function dispatch_walltime
  99  *
 100  * @abstract
 101  * Create a dispatch_time_t using the wall clock.
 102  *
 103  * @discussion
 104  * On Mac OS X the wall clock is based on gettimeofday(3).
 105  *
 106  * @param when
 107  * A struct timespec to add time to. If NULL is passed, then
 108  * dispatch_walltime() will use the result of gettimeofday(3).
 109  *
 110  * @param delta
 111  * Nanoseconds to add.
 112  *
 113  * @result
 114  * A new dispatch_time_t.
 115  */
 116 API_AVAILABLE(macos(10.6), ios(4.0))
 117 DISPATCH_EXPORT DISPATCH_WARN_RESULT DISPATCH_NOTHROW
 118 dispatch_time_t
 119 dispatch_walltime(const struct timespec *_Nullable when, int64_t delta);
 120
 121 __END_DECLS
 122
 123 DISPATCH_ASSUME_NONNULL_END
 124
 125 #endif