how to change the effective user identficator

>I can't change the EUID of a perl process which performs a perl script.
>I used the manual perlsec and wrote the script:
>
>#!/usr/bin/perl
>
>use English '-no_match_vars';
>
>$EUID = 0;
>open(THEFILE, ">/var/log/messages") || die "can't open file";
>print "The file was opened\n";
>#end of the script
>
>The script file has the rights:
>$chown root:root test.pl
>$chmod a+xs test.pl
>The script gives the error "can't open file"
>
>
>Daneel

[Forwarding to CLPM because CLP is obsolete]

>Jürgen Exner wrote:>
>
>I don't know what is CLPM. I didn't find definition of CLPM or CLP in

>manuals: perl, perltoc and perldoc CLPM. Please, hint where can I read
>about it.