Short answer: You cannot with Proc::Simple (longer: in your case when starting a
sub{...} as a child process)
This is what happens in the child part of the fork() that is executed for your $func = sub{...};
# in Proc::Simple
# $func = sub{ ... }; # your code
...
if(ref($func) eq "CODE") {
$self->dprt("Launching code");
$func->(@params); exit 0; # Start perl subroutine
} else {
...
So, the
exit 0 (successful execution) is all that is returned from your sub{...}.
The
$return value is discarded.
Your sub{...} could return the result to the main process by means of IPC or
by storing the result in a temporary file
(e.g. YAML, JSON, Storable, etc.). The parent process could read
the result from a pipe or load the serialised data from a file after the sub has finished.
Update: IPC::Lite
However, I guess, that in this particular case, you're better off with threads
and maybe a queue.