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Kafe Chang
Asked: 2018-03-16 10:15:33 +0800 CST

Simple C++ Thread Program Can't Be Compiled

  • 772

The following is my 1st multi-threaded program. But while it was compiled, there is a linking error. The part of the error message: 

std::thread::thread<void (&)(int), int&>(void (&)(int), int&):
test.cpp (.text._ZNSt6threadC2IRFviEJRiEEEOT_DpOT0_[_ZNSt6threadC5IRFviEJRiEEEOT_DpOT0_]+0x33): undefined reference pthread_create
collect2: error ld return 1

#include<thread>

void f(int i) {}

int main() {
        std::thread t(f, 1);
        t.join();
        return 0;
}
compiling c++ g++

4 Answers

  1. You need to compile with -pthread as a compile option.

    I got your code to compile with this (though I added the -Wall function to give me all warning notices):

    g++ -pthread -out foo.exe foo.cpp

    (where foo.cpp was the input filename I used containing your code)

    • 10

  2. Even if your program uses c++11's threading feature, you need to specify '-pthread' to successfully compile your program.

    Please read below thread for more info https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=763369

    • 1

  3. I had fixed the same Issue (undefined reference to Pthread_create) So the issue is not your Code but the argument which be have missed while generating object file in G++ compiler 

    void threadFun()
{
    cout<<"\n"<<"   "<<"INSIDE THREAD"<<"\n";
}

int main()
{
    thread t1(threadFun);
    t1.join();

    return 0;
}

    Here is the issue:

    This is how I fixed it:

    • 0

  4. you can take a look at this example:

    https://mockstacks.com/Cpp_Threading

    #include #include #include

    using namespace std;

    // The function we want to execute on the new thread. void task1(string msg) { cout << "task1 says: " << msg; }

    int main() { // Constructs the new thread and runs it. Does not block execution. thread t1(task1, "Hello");

    // Do other things...

    // Makes the main thread wait for the new thread to finish execution, therefore blocks its own execution. t1.join(); }

    • 0