The 40 makes sense now as well:
walter@ananas:0:~/srcelf/ucontext$ gcc qprof_bug_ucontext.c -g walter@ananas:0:~/srcelf/ucontext$ ./a.out | addr2line gregs is at extra + 40 /home/walter/srcelf/ucontext/main.c:18
The 40 makes sense now as well:
walter@ ananas: 0:~/srcelf/ ucontext$ gcc qprof_bug_ ucontext. c -g ananas: 0:~/srcelf/ ucontext$ ./a.out | addr2line srcelf/ ucontext/ main.c: 18
walter@
gregs is at extra + 40
/home/walter/