How to use PAPI with C++11 std:thread? - c++11

Question

I would like to use PAPI to get the overall counters of all C++11 std::thread threads in a program.
PAPI documentation on Threads says that:
Thread support in the PAPI library can be initialized by calling the following low-level function in C: int PAPI_thread_init(unsigned long(*handle)(void));
where the handle is a
Pointer to a routine that returns the current thread ID as an unsigned long.
For example, for pthreads the handle is pthread_self.
But, I have no idea what it should be with C++11 std::thread.
Nor if it makes more sense to use something different from PAPI.

Answer 1

C++11 threading support has the std::this_thread::get_id() function that returns a std::thread::id instance which can be serialized to a stream. Then you coud try to read an unsigned long from the stream and return ir. Something like this:
#include <thread>
#include <iostream>
#include <sstream>
unsigned long current_thread_id()
{
std::stringstream id_stream;
id_stream << std::this_thread::get_id();
unsigned long id;
id_stream >> id;
return id;
}
int main(int argc, char** argv)
{
std::cout << current_thread_id();
return 0;
}
So in this snippet the current_thread_id function is what you are looking for, but you should add proper error handling (the thread id may not always be a number, in that case you will not be able to read a number from the stream and you should handle that accordingly).
That being said, maybe just use GetCurrentThreadId , since you are already introducing the Linux specific pthread_self.