Is there really any difference between using & and not using & when calling a subroutine?
A1:
None that should concern you at this point. A subtle difference does exist between &foo and foo when subroutine prototypes are used or when a subroutine is called without parentheses. These are topics well beyond the scope of this book, but for the curious , they're documented in the perlsub manual page.
Q2:
When I use my($var) in a program, Perl responds with a syntax error, next 2 tokens my( message.
A2:
You either have mistyped something or have Perl version 4 installed. Type perl -v at a command prompt. If Perl responds with version 4, you should upgrade immediately.
Q3:
How do I pass (or return) functions, filehandles, multiple arrays, or hashes to a subroutine?
A3:
For passing functions, multiple arrays, and hashes, you need to use a reference, which is covered in Hour 13. For passing filehandles to and from a subroutine, you need to use either something called a typeglob or the IO::Handle module, both of which are beyond the scope of this book.
Q4:
A function I'm using returns many values, but I'm interested in only one. How do I skip some return values?
A4:
One method is to make a literal list out of the function by wrapping the entire function call in parentheses. When it's a list, you can use ordinary list slices to get pieces of the list. The following extracts just the year (current year minus 1900) from the built-in function localtime , which actually has nine return values:
print "It is now ", 1900+ (localtime)[5];
The other method is to assign the return value from the function into a list and simply assign the unwanted values to undef or a dummy variable:
