Why does this simple std::thread example not work?

Question

Tried the following example compiled with g++ -std=gnu++0x t1.cpp and g++ -std=c++0x t1.cpp but both of these result in the example aborting.

Answer 1

Simplest code to reproduce that error and how to fix:

Put this in a file called s.cpp:

#include 
#include 
#include 
#include 
#include 
using namespace std;
void task1(std::string msg){
  cout << "task1 says: " << msg;
}
int main(){
    std::thread t1(task1, "hello");
    usleep(1000000);
    t1.detach();
}

Compile like this:

el@apollo:~/foo7$ g++ -o s s.cpp -std=c++0x

Run it like this, the error happens:

el@apollo:~/foo7$ ./s
terminate called after throwing an instance of 'std::system_error'
  what():  Operation not permitted
Aborted (core dumped)

To fix it, compile it like this with the -pthread flag:

g++ -o s s.cpp -std=c++0x -pthread
./s

Then it works correctly:

task1 says: hello