如何分配线程本地存储？
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我的函数中有一个静态变量，但我希望每个线程都将其设为静态。
如何为C ++类分配内存，以便每个线程都有自己的类实例副本？
AnotherClass::threadSpecificAction()
{
// How to allocate this with thread local storage?
static MyClass *instance = new MyClass();
instance->doSomething();
}
没有找到相关结果
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9 个回复
诫商
#include <boost/thread/tss.hpp> static boost::thread_specific_ptr< MyClass> instance; if( ! instance.get() ) { // first time called by this thread // construct test element to be used in all subsequent calls from this thread instance.reset( new MyClass); } instance->doSomething();超可林
关键字。 这是存储期限说明符的示例：#include <iostream> #include <string> #include <thread> #include <mutex> thread_local unsigned int rage = 1; std::mutex cout_mutex; void increase_rage(const std::string& thread_name) { ++rage; std::lock_guard<std::mutex> lock(cout_mutex); std::cout << \"Rage counter for \" << thread_name << \": \" << rage << \'\\n\'; } int main() { std::thread a(increase_rage, \"a\"), b(increase_rage, \"b\"); increase_rage(\"main\"); a.join(); b.join(); return 0; }磁辫覆氓
是便携式解决方案的最佳方法。 在Linux和GCC上，您可以使用修饰符。 因此，您的实例变量将如下所示：疾桓
//declare static data members pthread_key_t AnotherClass::key_value; pthread_once_t AnotherClass::key_init_once = PTHREAD_ONCE_INIT; //declare static function void AnotherClass::init_key() { //while you can pass a NULL as the second argument, you //should pass some valid destrutor function that can properly //delete a pointer for your MyClass pthread_key_create(&key_value, NULL); } void AnotherClass::threadSpecificAction() { //Initialize the key value pthread_once(&key_init_once, init_key); //this is where the thread-specific pointer is obtained //if storage has already been allocated, it won\'t return NULL MyClass *instance = NULL; if ((instance = (MyClass*)pthread_getspecific(key_value)) == NULL) { instance = new MyClass; pthread_setspecific(key_value, (void*)instance); } instance->doSomething(); }痰嫉
AnotherClass::threadSpecificAction() { thread_local MyClass *instance = new MyClass(); instance->doSomething(); }淘圃跺枯替
蹦吃舷弦
魄龟呸筹
#if (_MSC_VER >= 1400) #ifndef thread_local #define thread_local __declspec(thread) #endif #endif嫩昧竞莫
，但只消耗一个，快4倍 比）。 如果您正在寻找本地存储线程的可移植实现，则此库是一个不错的选择。