> (Note that in Wikipedia, the CS definitions of "subroutine" and "function" are synonymous.)

Linking to the same page doesn't mean they are "synonymous".

WP entries on programming are written by programmers. If their main language is redefining a concept they'll take it as normative.

Compare the notion of "closure" in PHP for "anonymous subroutine" which is ... "unfortunate". In Python are anonymous subroutines aka "lambdas" restricted to one expression only which is ... "even more unfortunate".

IOW various WP authors will introduce their own truth.

Anyway this WP goes into some details to explain why the concept vary between different languages.

Some programming languages, such as Pascal, Fortran, Ada and many dialects of BASIC, distinguish between functions or function subprograms, which provide an explicit return value to the calling program, and subroutines or procedures, which do not. In those languages, function calls are normally embedded in expressions (e.g., a sqrt function may be called as y = z + sqrt(x)). Procedure calls either behave syntactically as statements (e.g., a print procedure may be called as if x > 0 then print(x) or are explicitly invoked by a statement such as CALL or GOSUB (e.g., call print(x)). Other languages, such as C and Lisp, do not distinguish between functions and subroutines.

In strictly functional programming languages such as Haskell, subprograms can have no side effects, which means that various internal states of the program will not change. Functions will always return the same result if repeatedly called with the same arguments. Such languages typically only support functions, since subroutines that do not return a value have no use unless they can cause a side effect.

In programming languages such as C, C++, and C#, subroutines may also simply be called functions, not to be confused with mathematical functions or functional programming, which are different concepts.

So subroutines and functions are synonymous in Perl, but not in general.

To be more precise Perl's sub is a meta construct implementing all features from procedures and functions like known in older languages, from this perspective the names are linguistically just "pars pro toto" in Perl.

In Perl you can use a sub like °

so the wordings become sometimes fuzzy.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

°) the listed items are not exclusive, there are overlaps.

In reply to Re^2: My problems to understand the Perl documentation by LanX
in thread My problems to understand the Perl documentation by bojinlund

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.