Section
std::recursive_mutex
The recursive_mutex class is a synchronization primitive that can be used to protect shared data from being simultaneously accessed by multiple threads.
# Declarations
class recursive_mutex;
(since C++11)
# Example
#include <iostream>
#include <mutex>
#include <thread>
class X
{
std::recursive_mutex m;
std::string shared;
public:
void fun1()
{
std::lock_guard<std::recursive_mutex> lk(m);
shared = "fun1";
std::cout << "in fun1, shared variable is now " << shared << '\n';
}
void fun2()
{
std::lock_guard<std::recursive_mutex> lk(m);
shared = "fun2";
std::cout << "in fun2, shared variable is now " << shared << '\n';
fun1(); // recursive lock becomes useful here
std::cout << "back in fun2, shared variable is " << shared << '\n';
}
};
int main()
{
X x;
std::thread t1(&X::fun1, &x);
std::thread t2(&X::fun2, &x);
t1.join();
t2.join();
}