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From: jlg@lanl.ARPA (Jim Giles)
Newsgroups: net.lang
Subject: Re:   [Really: C builtin functions?]
Message-ID: <2040@lanl.ARPA>
Date: Fri, 18-Apr-86 19:29:16 EST
Article-I.D.: lanl.2040
Posted: Fri Apr 18 19:29:16 1986
Date-Received: Sun, 20-Apr-86 17:09:45 EST
References: <443@3comvax.UUCP> <7900003@ztivax.UUCP>
Reply-To: jlg@a.UUCP (Jim Giles)
Organization: Los Alamos National Laboratory
Lines: 42
Keywords: C

In article <149@diablo.ARPA> avg@diablo.UUCP (Allen VanGelder) writes:
>I think there may be a confusion in terminology between built-in and
>in-line.  In FORTRAN, MAX is expanded in-line, so you always get
>FORTRAN's MAX.  But SIN is not, and if you jiggle your libraries
>properly you will get your personal SIN function.  The same is true
>for READ and WRITE in FORTRAN.

Actually, you CAN get your own MAX function from Fortran.  All you do
is type :

      EXTERNAL MAX
      .
      .
      I=MAX(A)
	...

Then you provide your own MAX function in a library that's searched before
the system default library is searched.

Furthermore, you can declare MAX to be a local variable:

      REAL MAX(0:500)
	...

In fact, if you use MAX in a way that is not syntactically the same as a
function reference, Fortran will automatically declare a variable of the
appropriate type (subject to the requirements of the IMPLICIT statement).

	...
      MAX=5
	...

In Fortran, ALL identifiers can be redefined by the user (there are some
reserved keywords - they are too long to be identifiers, this will change
with 8x which allows 31 character identifiers).  It could be worse - it could
be PL-I with conditional expressions:

I=if if then then else else; /* or something like this! Bletch.


J. Giles
Los Alamos