| /* |
| * Copyright (c) 2008-2010 Apple Inc. All rights reserved. |
| * |
| * @APPLE_APACHE_LICENSE_HEADER_START@ |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| * @APPLE_APACHE_LICENSE_HEADER_END@ |
| */ |
| |
| #ifndef __DISPATCH_ONCE__ |
| #define __DISPATCH_ONCE__ |
| |
| #ifndef __DISPATCH_INDIRECT__ |
| #error "Please #include <dispatch/dispatch.h> instead of this file directly." |
| #include <dispatch/base.h> // for HeaderDoc |
| #endif |
| |
| DISPATCH_ASSUME_NONNULL_BEGIN |
| |
| __BEGIN_DECLS |
| |
| /*! |
| * @typedef dispatch_once_t |
| * |
| * @abstract |
| * A predicate for use with dispatch_once(). It must be initialized to zero. |
| * Note: static and global variables default to zero. |
| */ |
| DISPATCH_SWIFT3_UNAVAILABLE("Use lazily initialized globals instead") |
| typedef long dispatch_once_t; |
| |
| /*! |
| * @function dispatch_once |
| * |
| * @abstract |
| * Execute a block once and only once. |
| * |
| * @param predicate |
| * A pointer to a dispatch_once_t that is used to test whether the block has |
| * completed or not. |
| * |
| * @param block |
| * The block to execute once. |
| * |
| * @discussion |
| * Always call dispatch_once() before using or testing any variables that are |
| * initialized by the block. |
| */ |
| #ifdef __BLOCKS__ |
| __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0) |
| DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW |
| DISPATCH_SWIFT3_UNAVAILABLE("Use lazily initialized globals instead") |
| void |
| dispatch_once(dispatch_once_t *predicate, |
| DISPATCH_NOESCAPE dispatch_block_t block); |
| |
| DISPATCH_INLINE DISPATCH_ALWAYS_INLINE DISPATCH_NONNULL_ALL DISPATCH_NOTHROW |
| DISPATCH_SWIFT3_UNAVAILABLE("Use lazily initialized globals instead") |
| void |
| _dispatch_once(dispatch_once_t *predicate, |
| DISPATCH_NOESCAPE dispatch_block_t block) |
| { |
| if (DISPATCH_EXPECT(*predicate, ~0l) != ~0l) { |
| dispatch_once(predicate, block); |
| } else { |
| dispatch_compiler_barrier(); |
| } |
| DISPATCH_COMPILER_CAN_ASSUME(*predicate == ~0l); |
| } |
| #undef dispatch_once |
| #define dispatch_once _dispatch_once |
| #endif |
| |
| __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0) |
| DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NONNULL3 DISPATCH_NOTHROW |
| DISPATCH_SWIFT3_UNAVAILABLE("Use lazily initialized globals instead") |
| void |
| dispatch_once_f(dispatch_once_t *predicate, void *_Nullable context, |
| dispatch_function_t function); |
| |
| DISPATCH_INLINE DISPATCH_ALWAYS_INLINE DISPATCH_NONNULL1 DISPATCH_NONNULL3 |
| DISPATCH_NOTHROW |
| DISPATCH_SWIFT3_UNAVAILABLE("Use lazily initialized globals instead") |
| void |
| _dispatch_once_f(dispatch_once_t *predicate, void *_Nullable context, |
| dispatch_function_t function) |
| { |
| if (DISPATCH_EXPECT(*predicate, ~0l) != ~0l) { |
| dispatch_once_f(predicate, context, function); |
| } else { |
| dispatch_compiler_barrier(); |
| } |
| DISPATCH_COMPILER_CAN_ASSUME(*predicate == ~0l); |
| } |
| #undef dispatch_once_f |
| #define dispatch_once_f _dispatch_once_f |
| |
| __END_DECLS |
| |
| DISPATCH_ASSUME_NONNULL_END |
| |
| #endif |