The single-threaded C++ program below compiles with or without -lpthread, but behaves differently.

The issue appears to be that libc.so provides an implementation of pthread_exit() that does not do stack-unwinding, but the libpthread.so version does do stack unwinding.

I believe that either behaviour complies with the standards, but it would be nice if glibc was consistent in its behaviour.

$ g++ -o temp temp.cc -pthread && ./temp
Hi there!
$ g++ -o temp temp.cc && ./temp
(no output)

This is Fedora glibc-2.23.1-10.fc24.x86_64

-----------------------------

#include <pthread.h>
#include <stdio.h>

struct Foo {
    ~Foo() {
        printf("Hi there!\n");
    }
};

int main()
{
    Foo foo;
    pthread_exit(NULL);
    return 0;
}