Why does gdb evaluate sqrt(3) to 0?

Question

The square root of 3, as estimated by Wolfram Alpha:

1.7320508075688772935274463415058723669428052538103806280558...

When I do sqrt(3

Answer 1

To call a function without debug info, you must explicitly tell gdb the type for the return and arguments, using a function pointer cast. So, for your example:

(gdb) print ((double (*) (double)) sqrt) (3)
$1 = 1.7320508075688772