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From: markh@csd4.csd.uwm.edu (Mark William Hopkins)
Newsgroups: comp.lang.c
Subject: Re: realloc((char *)NULL,size) - how standard ?
Message-ID: <9908@uwm.edu>
Date: 4 Mar 91 17:37:44 GMT
References: <15112:Feb2419:11:4391@kramden.acf.nyu.edu> <941@caslon.cs.arizona.edu> <1991Feb25.053353.12842@athena.mit.edu>
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dave@cs.arizona.edu (Dave P. Schaumann) writes:
> Actually, if you want to port code that passes NULL to realloc to a machine
> that doesn't like that, all you have to do is this:
> [write correct routine called Realloc]
> Then, just #define realloc Realloc anywhere you need to.

In article <1991Feb25.053353.12842@athena.mit.edu> scs@adam.mit.edu writes:
>This is the right approach, but it's much better (if you care
>about widespread portability) to use a name like xrealloc instead
>of Realloc.  "Realloc" is not a good name for a wrapper function
>around realloc, because it is not distinct under a monocase
>linker.

The realloc problem is a red-herring.  All you have to do hide this away
somewhere in an include file:

#define xalloc(Loc, Bytes) \
   ((Loc) == NULL? malloc(Bytes): realloc((Loc), (Bytes)))

and don't use anything but xalloc...

You could even add in an #if section to define xalloc as realloc for standard
C.  And while you're at it, you might as well put in a couple more definitions
like:

#define make(Loc, Type) ((Type *)xalloc(Loc, sizeof(Type)))
#define break(Loc) (free((char *)Loc))

just to fatten up the include file...