std::thread::join
void join(); |
(since C++11) | |
Blocks the current thread until the thread identified by *this finishes its execution.
The completion of the thread identified by *this synchronizes with the corresponding successful return from join().
No synchronization is performed on *this itself. Concurrently calling join() on the same std::thread
object from multiple threads constitutes a data race that results in undefined behavior.
Parameters
(none)
Return value
(none)
Postconditions
joinable() is false
Exceptions
std::system_error if an error occurs.
Error Conditions
- resource_deadlock_would_occur if this->get_id() == std::this_thread::get_id() (deadlock detected)
- no_such_process if the thread is not valid
- invalid_argument if joinable() is false
Example
Run this code
#include <iostream> #include <thread> #include <chrono> void foo() { // simulate expensive operation std::this_thread::sleep_for(std::chrono::seconds(1)); } void bar() { // simulate expensive operation std::this_thread::sleep_for(std::chrono::seconds(1)); } int main() { std::cout << "starting first helper...\n"; std::thread helper1(foo); std::cout << "starting second helper...\n"; std::thread helper2(bar); std::cout << "waiting for helpers to finish..." << std::endl; helper1.join(); helper2.join(); std::cout << "done!\n"; }
Output:
starting first helper... starting second helper... waiting for helpers to finish... done!
References
- C++11 standard (ISO/IEC 14882:2011):
- 30.3.1.5 thread members [thread.thread.member]
See also
permits the thread to execute independently from the thread handle (public member function) | |
checks whether the thread is joinable, i.e. potentially running in parallel context (public member function) |