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 #ifdef NSEC_PER_SEC
  37 #undef NSEC_PER_SEC
  38 #endif
  39 #ifdef USEC_PER_SEC
  40 #undef USEC_PER_SEC
  41 #endif
  42 #ifdef NSEC_PER_USEC
  43 #undef NSEC_PER_USEC
  44 #endif
  45 #ifdef NSEC_PER_MSEC
  46 #undef NSEC_PER_MSEC
  47 #endif
  48 #define NSEC_PER_SEC 1000000000ull
  49 #define NSEC_PER_MSEC 1000000ull
  50 #define USEC_PER_SEC 1000000ull
  51 #define NSEC_PER_USEC 1000ull
  52
  53 __BEGIN_DECLS
  54
  55 struct timespec;
  56
  57 /*!
  58  * @typedef dispatch_time_t
  59  *
  60  * @abstract
  61  * A somewhat abstract representation of time; where zero means "now" and
  62  * DISPATCH_TIME_FOREVER means "infinity" and every value in between is an
  63  * opaque encoding.
  64  */
  65 typedef uint64_t dispatch_time_t;
  66
  67 #define DISPATCH_TIME_NOW (0ull)
  68 #define DISPATCH_TIME_FOREVER (~0ull)
  69
  70 /*!
  71  * @function dispatch_time
  72  *
  73  * @abstract
  74  * Create dispatch_time_t relative to the default clock or modify an existing
  75  * dispatch_time_t.
  76  *
  77  * @discussion
  78  * On Mac OS X the default clock is based on mach_absolute_time().
  79  *
  80  * @param when
  81  * An optional dispatch_time_t to add nanoseconds to. If zero is passed, then
  82  * dispatch_time() will use the result of mach_absolute_time().
  83  *
  84  * @param delta
  85  * Nanoseconds to add.
  86  *
  87  * @result
  88  * A new dispatch_time_t.
  89  */
  90 __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0)
  91 DISPATCH_EXPORT DISPATCH_WARN_RESULT DISPATCH_NOTHROW
  92 dispatch_time_t
  93 dispatch_time(dispatch_time_t when, int64_t delta);
  94
  95 /*!
  96  * @function dispatch_walltime
  97  *
  98  * @abstract
  99  * Create a dispatch_time_t using the wall clock.
 100  *
 101  * @discussion
 102  * On Mac OS X the wall clock is based on gettimeofday(3).
 103  *
 104  * @param when
 105  * A struct timespect to add time to. If NULL is passed, then
 106  * dispatch_walltime() will use the result of gettimeofday(3).
 107  *
 108  * @param delta
 109  * Nanoseconds to add.
 110  *
 111  * @result
 112  * A new dispatch_time_t.
 113  */
 114 __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0)
 115 DISPATCH_EXPORT DISPATCH_WARN_RESULT DISPATCH_NOTHROW
 116 dispatch_time_t
 117 dispatch_walltime(const struct timespec *when, int64_t delta);
 118
 119 __END_DECLS
 120
 121 #endif