osd@hou2d.UUCP (Orlando Sotomayor-Diaz) (10/11/85)
From: Orlando Sotomayor-Diaz (The Moderator) <cbosgd!std-c>
mod.std.c Digest Fri, 11 Oct 85 Volume 11 : Issue 2
Today's Topics:
#elif
Function prototypes
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Date: Mon, 7 Oct 85 21:24:27 EDT
From: Doug Gwyn (VLD/VMB) <gwyn@BRL.ARPA>
Subject: #elif
To: cbosgd!std-c@LOCAL.Berkeley.EDU
In the April 30, 1985 X3J11/85-045, section C.8, the #elif
directive is not explained and the term "control condition"
is used but not defined (presumably it means "controlling
constant expression"). I think the paragraph that mentions
"control condition" is attempting to include #elif, but
that is not clear.
Also, when skipping, "directives are verified for
correctness, but processed only to keep track of the level
of nested conditionals"; what does this mean? (Lines
starting with # checked for a known preprocessing keyword
after the # ? There is a limit to what can be checked in
the code being skipped.)
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Date: Thu, 10 Oct 85 15:59:29 mdt
From: ihnp4!alberta!myrias!cg (Chris Gray)
Subject: Function prototypes
To: alberta!ihnp4!cbosgd!std-c
A question of interpretation about function prototypes:
Does the use of the new style function headers in a function definition
qualify as a 'function prototype being in scope' for that function?
For example:
void f(float p) {
if (p >= 0.0)
f(p - 1.0);
}
Is 'p - 1.0' passed to the recursive call as a 'float' or as a 'double'?
Both cases are self-consistent, but which is in effect will affect what
other callers of 'f' are supposed to do. If this style of header doesn't
constitute a function prototype, do I really have to do this:
extern void f(float p);
static void f(float p)
{
...
}
The sentence reading "The following equivalent definition uses the prototype
form for the parameter declarations:" from the end of the second paragraph
on page 60 of the April 30 ANSI draft seems to imply that I really do have
to use the second form. I would suggest that the use of the prototype form
constitute an actual prototype. The alternative is that new-style functions
must ALWAYS have a prototype in scope in the file they are defined in.
This seems unnecessarily ugly. Allowing the prototype form to BE a prototype
won't break any existing programs since they won't be using it.
Chris Gray {...,ihnp4}!alberta!myrias!cg
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End of mod.std.c Digest - Fri, 11 Oct 85 07:43:53 EDT
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