Thread get_id() function in C++ (original) (raw)

Last Updated : 16 Jun, 2021

Thread::get_id() is an in-built function in C++ std::thread. It is an observer function which means it observes a state and then returns the corresponding output. This function returns the value of std::thread::id thus identifying the thread associated with *this.
Syntax:

thread_name.get_id();

Parameters: This function does not accept any parameters.
Return Value: This method returns a value of type std::thread::id identifying the thread associated with *this i.e. the thread which was used to call the get_id function is returned. The default constructed std::thread::id is returned when no such thread is identified.
Below examples demonstrates the use of std::thread::get_id() method:
Note: On the online IDE this program will show error. To compile this, use the flag “-pthread” on g++ compilers compilation with the help of command “g++ –std=c++14 -pthread file.cpp”.

CPP `

// C++ program to demonstrate the use of // std::thread::get_id

#include #include #include using namespace std;

// util function for thread creation void sleepThread() { this_thread::sleep_for(chrono::seconds(1)); }

int main() { // creating thread1 and thread2

thread thread1(sleepThread);
thread thread2(sleepThread);

thread::id t1_id = thread1.get_id();
thread::id t2_id = thread2.get_id();

cout << "ID associated with thread1= "
     << t1_id << endl;
cout << "ID associated with thread2= "
     << t2_id << endl;

thread1.join();
thread2.join();

return 0;

}

`

Possible Output:

ID associated with thread1= 139858743162624 ID associated with thread2= 139858734769920