# SYPH1.pm
package SYPH1;
$SYPH1::VERSION = '0.01';
1;

##</code><code>##

# SYPH2.pm
package SYPH2;
if(defined $INC{'SYPH1.pm'}) {print "SYPH1.pm loaded\n"}
else {print "SYPH1.pm NOT loaded\n"}
1;

##</code><code>##

D:\>set PERL5OPT=

D:\>perl -MSYPH1 -MSYPH2 -e ""
SYPH1.pm loaded

D:\>perl -MSYPH1 -e "use SYPH2"
SYPH1.pm loaded

D:\>set PERL5OPT=-MSYPH1

D:\>perl -e "use SYPH2"
SYPH1.pm loaded

D:\>perl -MSYPH2 -e ""
SYPH1.pm NOT loaded

D:\>