Thanks - that's great. I can see what I want to do now. Actually it's the require STRING flavour I'm dealing with, so it's maybe a bit easier than I thought. All I want to do is to make sure the subs using Maybe::Module don't blow up when called. I'm doing something like:

my $no_go;
BEGIN {
    eval { require Maybe::Module };
    if ( $@ ) { $no_go = 1 }
}

sub my_function {
    print "I'm the normal definition";
}

# ...

if ( $no_go ) {
    # safe definition
    *my_function = sub { carp "Function not available without Maybe::M
+odule" };
}

1;
[download]

This works nicely for me; as an aside, I wonder why the BEGIN block can see the my $no_go? I would have expected the BEGIN to run first and so to complain about $no_go failing strict;

Thanks again
ViceRaid