On Tue, May 22, 2018 at 3:32 AM, Michael Paquier <michael@paquier.xyz> wrote:
<snip> And this maps with any C code.
The important differences here are:
*) Declaring a C function as void prevents returning a value. The intent not to return a value is clear to any caller and is enforced by the compiler. There is no equivalent protection in Perl.
*) Falling off the end of a C function that returns a type other than void has undefined results. Perl will always return the value of the last statement executed.
Because Perl does allow returning a value without explicitly using return, it's easy to write code that breaks if an unwary person adds a line to the end of the subroutine. There's a common constructor incantation that has this problem. It's a real gotcha for C programmers just starting to poke around in Perl code.
This difference also allows users of .pm modules to abuse the API of a method intended to be "void", if the value returned falling off the end happens to seem useful, leading to breakage if the method's code changes in the future.
