To the best of my knowledge neither CGI nor CGI::Simple give you a way to populate header information directly into their respective objects; they just pull it from ENV automatically. Those are the only two CGI-related modules I've personally worked with; there may be others. A quick experiment shows you can localize %ENV though: 
#!perl -l
sub foo {
  local %ENV;
  $ENV{foo} = '1';
  print $ENV{foo};
}
foo;
print 'yes' if $ENV{foo} eq '1';

[download]
doesn't print "yes"

In reply to Re: Populate CGI from HTTP::Request wo/ using %ENV ? by Errto
in thread Populate CGI from HTTP::Request wo/ using %ENV ? by renodino

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