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Editing: compatibility.h
// -*- C++ -*- // Copyright (C) 2007-2018 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the terms // of the GNU General Public License as published by the Free Software // Foundation; either version 3, or (at your option) any later // version. // This library is distributed in the hope that it will be useful, but // WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** @file parallel/compatibility.h * @brief Compatibility layer, mostly concerned with atomic operations. * * This file is a GNU parallel extension to the Standard C++ Library * and contains implementation details for the library's internal use. */ // Written by Felix Putze. #ifndef _GLIBCXX_PARALLEL_COMPATIBILITY_H #define _GLIBCXX_PARALLEL_COMPATIBILITY_H 1 #include <parallel/types.h> #include <parallel/base.h> #if !defined(_WIN32) || defined (__CYGWIN__) #include <sched.h> #endif #ifdef __MINGW32__ // Including <windows.h> will drag in all the windows32 names. Since // that can cause user code portability problems, we just declare the // one needed function here. extern "C" __attribute((dllimport)) void __attribute__((stdcall)) Sleep (unsigned long); #endif namespace __gnu_parallel { template<typename _Tp> inline _Tp __add_omp(volatile _Tp* __ptr, _Tp __addend) { int64_t __res; #pragma omp critical { __res = *__ptr; *(__ptr) += __addend; } return __res; } /** @brief Add a value to a variable, atomically. * * @param __ptr Pointer to a signed integer. * @param __addend Value to add. */ template<typename _Tp> inline _Tp __fetch_and_add(volatile _Tp* __ptr, _Tp __addend) { if (__atomic_always_lock_free(sizeof(_Tp), __ptr)) return __atomic_fetch_add(__ptr, __addend, __ATOMIC_ACQ_REL); return __add_omp(__ptr, __addend); } template<typename _Tp> inline bool __cas_omp(volatile _Tp* __ptr, _Tp __comparand, _Tp __replacement) { bool __res = false; #pragma omp critical { if (*__ptr == __comparand) { *__ptr = __replacement; __res = true; } } return __res; } /** @brief Compare-and-swap * * Compare @c *__ptr and @c __comparand. If equal, let @c * *__ptr=__replacement and return @c true, return @c false otherwise. * * @param __ptr Pointer to signed integer. * @param __comparand Compare value. * @param __replacement Replacement value. */ template<typename _Tp> inline bool __compare_and_swap(volatile _Tp* __ptr, _Tp __comparand, _Tp __replacement) { if (__atomic_always_lock_free(sizeof(_Tp), __ptr)) return __atomic_compare_exchange_n(__ptr, &__comparand, __replacement, false, __ATOMIC_ACQ_REL, __ATOMIC_RELAXED); return __cas_omp(__ptr, __comparand, __replacement); } /** @brief Yield control to another thread, without waiting for * the end of the time slice. */ inline void __yield() { #if defined (_WIN32) && !defined (__CYGWIN__) Sleep(0); #else sched_yield(); #endif } } // end namespace #endif /* _GLIBCXX_PARALLEL_COMPATIBILITY_H */
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