This is because your constants only exist in the namespace of your "header" file. What use constant camel => "flea-ridden" actually does is create a subroutine in the caller's namespace that returns the constant (and is normally inlined by the compiler).

Because said subroutine only exists in the namespace of your header file, your main program cannot access it. There are however a number of ways for your program to access this constant. Assuming header.pm contains your constants, and program.pl is your script

• Make header.pm a package that exports your constants:

  package header;
  @ISA=('Exporter');
  @EXPORT=('camel');
  use constant camel => 'flea-ridden';
  1; # I'm a well-behaving module
  [download]

  Program.pl can then use header; and just access camel as normal.
• Another option is to play symbol table games: program.pl copies the subs into it's own namespace.

  # program.pl
  use header;
  *header::camel=*::camel;
  print &camel;
  # Note that you have to call camel as a function here.
  [download]

• I have this nagging feeling that there are some tricks you can pull with eval or require, but I can't think of some right now. Undoubtedly, someone else will soon enough :).

CU
Robartes-

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