Path: utzoo!attcan!uunet!ncrlnk!ncrcae!ece-csc!ncsuvx!gatech!rutgers!att!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c
Subject: Re: Dynamically malloc()-able pointers in a struct?
Message-ID: <8597@alice.UUCP>
Date: 24 Dec 88 14:41:23 GMT
References: <448@blake.acs.washington.edu>
Distribution: na
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 32

In article <448@blake.acs.washington.edu>, phaedra@blake.acs.washington.edu (J. Anderson) writes:
> struct xyzzy {
> 	int plugh;
> 	long black_rod;
> 	char *foobar;	/* This wants to be a pointer to a variable-length
> 			 * array
> 			 */
> }

Nothing particularly hard about this, except that you must
allocate two separate areas of memory, one for an `xyzzy' object
and one for the character array addressed by `foobar'.  The
`xyzzy' object may be a local variable, of course:

	struct xyzzy a;
	a.foobar = malloc(n);

If you want the `xyzzy' object to be dynamic as well, do this:

	struct xyzzy *p;
	p = (struct xyzzy *) malloc (sizeof(struct xyzzy));
	p->foobar = malloc(n);

To free it, reverse the process:

	free(p->foobar);
	free(p);

What's the problem?
-- 
				--Andrew Koenig
				  ark@europa.att.com