Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!usc!ginosko!uunet!opusys!rlkd
From: rlkd@opusys.UUCP (R.L.K.Dattatri)
Newsgroups: comp.lang.c
Subject: C puzzle
Keywords: arrays, compilers
Message-ID: <404@opusys.UUCP>
Date: 24 Aug 89 00:14:03 GMT
Organization: Opus Systems, Cupertino, CA
Lines: 40


Here is a small puzzle.
The program below will compile and run on some compilers but will\
not compile on others.

main()
{
	int *p;

	p = (int *) malloc(1024);
	test_it(p);
}
test_it (x)
int (*x)[];
/* If a dimension is specified all compilers will accept it */
{
	int i;

	for (i=0; i < 10; ++i)
		(*x)[i] = i;
	/* x++; */
}

The parameter 'x' in test_it without dimensions works on some compilers
but others complain incomplete array'.
I can understand that the compiler is trying to guess the size of the rows
in the array. But that should come only when the commented x++ is used.
Without the dimension all compilers generated an increment of 'int' size for
'x++' but with the dimension it was the size of dimension * int size.

Does ANSI specify anything in this regard?

|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
| Mr. R.L.K. Dattatri       (408) 446-2110 (W)     |~~~~~|                 |
| Opus Systems              (408) 243-5140 (H)     |_____|                 |
| 20863 Bldg 400                                   |\   |   |/ |~~\        |
| Stevens Creek, Cupertino                         |  \ [___|\ |   |       |
| California, 95014                                     \      |   |       |
| E-mail: {uunet,sun}!opusys!rlkd  FAX: (408) 446-5009    \    |__/        |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~