I use macros extensively as well.  It makes code easier to write, easier=20
to read and easier to maintain.  But there ARE things to watch out for. =20
Once a macro is written and placed out of sight, it is easy to forget it=20
even IS a macro.

The classic example:

#define TOUPPER(c)  ('a' <=3D (c) && (c) <=3D 'z' ? (c) - 'a' + 'A' : (c))

works great, until you use

	selection =3D TOUPPER(getch());

which expands to

	('a' <=3D (getch()) && (getch()) <=3D 'z' ? (getch()) - 'a' + 'A' : (getch=
()))

and it goes to the keyboard 4 times when it seems to do so only once.

Kerry


James Newton wrote:
> Fine.
>
> I've written rather a lot of code and I use macros extensively to make th=
at
> code more configurable, flexible, and easier to read. I've never been bit=
ten
> by anything I would call "macro misuse", I have no idea why anyone would
> have trouble with them, and you made a general statement without any
> reference or proof so I assumed you were objecting to the language as a
> whole.=20
>
> If you can point out any danger from the macros I'm sharing, please give =
an
> example or reference and I'll apologize. If you just want to wave flags i=
n
> the air without actually being helpful, go away.
>
> --
> James Newton
> 1-970-462-7764=20
>
> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf =
Of
> Michael Watterson
> Sent: Monday, July 11, 2011 03:20
> To: Microcontroller discussion list - Public.
> Subject: Re: [PIC] Using macros to simplify port operations in C
>
> On 11/07/2011 01:39, James Newton wrote:
>  =20
>> Oh please.. I am REALLY not up for the C vs ASM debate. Please go play
>>    =20
> with
>  =20
>> your toys and leave this discussion to the adults?
>>
>>    =20
>
> I'd use C in preference to ASM any day. I wasn't at all suggesting ASM.=20
> Just sounding a warning.
>
> Really I don't believe in ASM except for some inline use or very small=20
> project.
>
> There is no need to be rude. Macro misuse is one of the biggest source=20
> of bugs in C programs. Not checking string real size and only relying on=
=20
> Null termination is the other.
>  =20

--=20
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