Question

Which is more efficient statement –> goto &fun($val) or fun($val) in perl ?
When to use which statement for better performance ?
Please let me know the answer !

Answer 1

I think this is the wrong question to ask.

The form fun($val) is the standard way to call another subroutine in perl.

The form goto &func is normally used to transfer control to another sub while removing the current stack frame. In addition, @_ is passed unaltered to the called routine.

The removal of the stack frame means that caller() will not see it, so that the &func will think that t was called by the caller of the routine which performed the goto. It also means that performing a backtrace in the debugger will not reveal the routine performing the goto.

If you want to preserve the calling stack frame but pass control to a function with the current setting of @_, then use return &func.

The form goto &func($val) is parsed as:

my $label = &func($val);
goto $label;

This will likely give a Can't find label ... error.

Examples:

sub func {
  my $x = shift;
  print "x = $x\n";
  my ($package, $file, $line) = caller();
  print "caller file: $file, line: $line\n";
}

sub foo {
  goto &func("from goto bar");
}

sub baz {
  return &func;
}

sub quux {
   goto &func;
}

baz("from baz");
quux("from quux");
foo("from foo");