5.1. A note about Safe

You can access all objects associated with the catalog and the user settings with opcode restrictions based on the standard Perl module Safe.pm. There are some unique things to know about programming with Interchange.

Under Safe, certain things cannot be used. For instance, the following can not be used when running Safe:

   $variable = `cat file/contents`;

The backtick operator violates a number of the default Safe opcode restrictions. Also, direct file opens can not be used. For example:

   open(SOMETHING, "something.txt")
       or die;

This will also cause a trap, and the code will fail to compile. However, equivalent Interchange routines can be used:

   # This will work if your administrator doesn't have NoAbsolute set
   $users = $Tag->file('/home/you/list');

   # This will always work, file names are based in the catalog directory
   $users = $Tag->file('userlist');