Compiling multithread code with g++

The answer was provided by a kind member of SO C++ chat.

It looks like this behaviour is caused by a bug in gcc.

The workaround provided in the last comment of that bug discussion does work and solves the issue:

-Wl,--no-as-needed

Adding -lpthread fixed the identical problem for me:

 g++ -std=c++11 foo.cpp -lpthread -o foo

I have slightly more advanced version (4.8.4 instead of 4.8.1), and I tested all three answers above. In fact:

-pthread alone works:

g++ -std=c++11 -o main -pthread main.cpp

-Wl,--no-as-needed alone does not work.

-lpthread alone does not work.

-Wl,--no-as-needed and -lpthread together work:

g++ -std=c++11 -o main -Wl,--no-as-needed main.cpp -lpthread

My version is "g++ (Ubuntu 4.8.4-2ubuntu1~14.04.1) 4.8.4".