How to inspect the return value of a function in GDB?

Question

Is it possible to inspect the return value of a function in gdb assuming the return value is not assigned to a variable?

Answer 1

Yes, just examine the EAX register by typing print $eax. For most functions, the return value is stored in that register, even if it's not used.

The exceptions to this are functions returning types larger than 32 bits, specifically 64-bit integers (long long), doubles, and structs or classes.

The other exception is if you're not running on an Intel architecture. In that case, you'll have to figure out which register is used, if any.