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From: lmiller@venera.isi.edu.UUCP
Newsgroups: comp.lang.c,news.software.b
Subject: Re: passing NULL to functions
Message-ID: <2671@venera.isi.edu>
Date: Wed, 6-May-87 12:16:47 EDT
Article-I.D.: venera.2671
Posted: Wed May  6 12:16:47 1987
Date-Received: Sat, 9-May-87 06:21:52 EDT
References: <150@sds.UUCP> <1129@ius2.cs.cmu.edu> <5804@brl-smoke.ARPA> <4724@utcsri.UUCP> <728@sdchema.sdchem.UUCP>
Reply-To: lmiller@venera.isi.edu.UUCP (Larry Miller)
Organization: Information Sciences Institute, Univ. of So. California
Lines: 36
Xref: utgpu comp.lang.c:2019 news.software.b:574

In article <728@sdchema.sdchem.UUCP> tps@sdchemf.UUCP (Tom Stockfisch) writes:
>In article <4724@utcsri.UUCP> greg@utcsri.UUCP (Gregory Smith) writes:
>
>>>In article <1129@ius2.cs.cmu.edu> edw@ius2.cs.cmu.edu (Eddie Wyatt) writes:
>
>>>>#define alloc(type)		((type *) malloc(sizeof(type)))
>
>>...problem...is that (type *) is not always a
>>cast to pointer to type: e.g.  int (*)() means pointer to func returning int,
>>but ( int (*)() * ) means you get a syntax error.
>>
>>There is no cure for this; it is a result of C's bass-ackward type syntax.
>
>>Greg Smith     University of Toronto      UUCP: ..utzoo!utcsri!greg

ETC.

The type of (int (*)()) is "pointer to function returning int".  If this is
the type in the allocation (type *) malloc(sizeof(type)), then we're
allocating space for a "function returning int".  I don't think we can do
that.  Here's a little prorgram, and the output of lint (4.3 UNIX on VAX
8650).

#include <stdio.h>
main()
{
  int (*x)();		/* ptr to function returning int */

  x = (int (*)()) malloc (sizeof (int ());
}

test.c:
test.c(6): compiler error: compiler takes size of function

Larry Miller
lmiller@venera.isi.edu