Date: Wed, 10 Jan 1996 21:07:42 -0600 (CST)
From: Aaron Ucko <UCKO AT VAX1 DOT ROCKHURST DOT EDU>
Subject: Re: (none)
To: enrico AT max DOT tiac DOT net
Cc: djgpp AT delorie DOT com
Message-id: <01HZUXQMXR2A000SKM@VAX1.ROCKHURST.EDU>
Organization: Rockhurst College; Kansas City, MO
MIME-version: 1.0

>> 	if (!my_pointer)
>> 		my_pointer = (my_struct_t *)malloc( sizeof (my_struct_t) ); 
>> 
>> Or BETTER CODE but equivalent:
>> 
>> 	if (my_pointer == (my_struct_t *)NULL)
>> 		...
>
>	You shouldn't need to cast NULL, I don't think...  

That's generally correct--NULL is generally #defined as something like
(void *)0, and everything can be converted to void *.

>	Either way, even better than that would be:
>	if (NULL == my_pointer) ...
>	since this will give you a compiler error if you make a typo and 
>only use one equal sign.  (Otherwise, it is an assignment, which can 
>cause no end of problems.  It's also a PAIN to find, when you do do it.)

Really?  GCC's -Wall flag enables -Wparentheses, which triggers the message
<filename>:<lineno>: warning: suggest parentheses around assignment used as
truth value

-- Aaron Ucko (ucko AT vax1 DOT rockhurst DOT edu; finger for PGP public key) | httyp!
"That's right," he said. "We're philosophers. We think, therefore we am."
-- Terry Pratchett, _Small Gods_ | Geek Code 3.1 [for explanation, finger 
 hayden AT mankato DOT msus DOT edu]: GCS/M/S/C d- s: a18 C++(+++)>++++ UL++>++++ P++ 
 L++>+++++ E- W(-) N++(+) o+ K- w--- O M@ V-(--) PS++(+++) PE- Y(+) PGP(+) t(+)
 !5 X-- R(-) tv-@ b++(+++) DI+ !D-- G++(+++) e->+++++(*) h!>+ r-(--)>+++ y?