well, providing all else fails, you can still backtick it... $file = `/bin/gunzip -c file.gz`; will send the output to STDOUT, which will be placed in $file for you to play with.
It's ugly, but it works.
-Syn0

word of caution: if you plan on using a variable for the filename and it comes from untrusted sources, make sure you have taint mode on and do proper checking on what is in the variable... backticks are evil evil little creatures.