1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include <algorithm> 10 #include <random> 11 12 #ifndef _LIBCPP_HAS_NO_THREADS 13 # include <mutex> 14 # if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB) 15 # pragma comment(lib, "pthread") 16 # endif 17 #endif 18 19 _LIBCPP_BEGIN_NAMESPACE_STD 20 21 #ifndef _LIBCPP_HAS_NO_THREADS 22 static constinit __libcpp_mutex_t __rs_mut = _LIBCPP_MUTEX_INITIALIZER; 23 #endif 24 unsigned __rs_default::__c_ = 0; 25 26 __rs_default::__rs_default() { 27 #ifndef _LIBCPP_HAS_NO_THREADS 28 __libcpp_mutex_lock(&__rs_mut); 29 #endif 30 __c_ = 1; 31 } 32 33 __rs_default::__rs_default(const __rs_default&) { ++__c_; } 34 35 __rs_default::~__rs_default() { 36 #ifndef _LIBCPP_HAS_NO_THREADS 37 if (--__c_ == 0) 38 __libcpp_mutex_unlock(&__rs_mut); 39 #else 40 --__c_; 41 #endif 42 } 43 44 __rs_default::result_type __rs_default::operator()() { 45 static mt19937 __rs_g; 46 return __rs_g(); 47 } 48 49 __rs_default __rs_get() { return __rs_default(); } 50 51 _LIBCPP_END_NAMESPACE_STD 52