How can I tell if used modules are pure perl?

Question

If I have Perl code which usees a lot of modules, is there a fast and easy way to find out if some of this modules are not pure Perl modules?

Answer 1

@DynaLoader::dl_modules contains the list of XS modules loaded.

perl -MSome::Module1 -MSome::Module2 -M... \
   -MDynaLoader -E'say for sort @DynaLoader::dl_modules;'

Or if you wanted to write it as a script:

# Usage: script Some::Module1 Some::Module2 ...

use 5.010;
use DynaLoader qw( );

while (defined($_ = shift(@ARGV))) {
   s{::}{/}g;
   $_ .= ".pm";
   require $_;
}

say for sort @DynaLoader::dl_modules;

Of course, nothing's stopping you from putting it in an existing script either.

use 5.010;
use DynaLoader qw( );
END { say for sort @DynaLoader::dl_modules; }

Answer 2

This looks like a job for what I call a "blowup sensor". You could just boobytrap the hooks, by putting this at the top of the first module:

BEGIN { 
    require Carp; #Does the stack stuff
    # Fool Perl into thinking that these are already loaded.
    @INC{ 'XSLoader.pm', 'DynaLoader.pm' } = ( 1, 1 );

    # overload boobytrapped stubs
    sub XSLoader::load        { Carp::confess( 'NOT Pure Perl!' ); }
    sub DynaLoader::bootstrap { Carp::confess( 'NOT Pure Perl!' ); }
}