How does gdb retrieve the exit code of target program?

Question

Under command line, I know that using echo $? gets me the exit code. In gdb, I use "r" to run through the program and the program terminates, so how does gdb gets this exit code? Any commands inside gdb?

Thanks!

Answer 1

When a program exits, gdb sets the convenience variable $_exitcode to the exit code.

So given:

int main() {
  return 23;
}

Running it in gdb, I get:

(gdb) run
Starting program: /tmp/q 
[Inferior 1 (process 3677) exited with code 027]
(gdb) print $_exitcode
$1 = 23