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| From | Joe Pfeiffer <pfeiffer@cs.nmsu.edu> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: #define BYTES *8 |
| Date | 2012-08-29 22:20 -0600 |
| Organization | A noiseless patient Spider |
| Message-ID | <1bfw75ko3e.fsf@pfeifferfamily.net> (permalink) |
| References | <k1hssn$c4o$1@reader1.panix.com> |
JohnF <john@please.see.sig.for.email.com> writes:
> Anything wrong with that, i.e., with #define BYTES *8
> to multiply by 8? It looked a little weird to me, but
> the more obvious #define BYTES(x) ((x)*8) isn't what
> I wanted to write. This was to express units of measurement,
> e.g., int bits = so_many BYTES; rather than
> int bits=BYTES(so_many); . I just wanted to read and write
> it the first way, and my test program
> #define BYTES *8
> #include <stdio.h>
> int main ( int argc, char *argv[] ) {
> int bytes=(argc<2?1:atoi(argv[1])),
> bits = bytes BYTES;
> printf("%d bytes = %d bits\n",bytes,bits);
> return(0); }
> works fine (and compiles with no -pedantic warnings).
> But that #define BYTES *8 still looks a little funky to me.
> I realize 2+2 BYTES must be written (2+2)BYTES, but is there
> any other kind of "gotcha"?
That way lies madness. Using macroes to invent new syntax for C is a
Bad Idea. It looks good when you come up with it, it looks good when
you first code it up, it turns out to be a disaster some time down the
road when you're maintaining it. There's nothing particularly wrong
with the specific macro you're suggesting (except possible surprises
with operator precedence), but typically when people do that they also
define a bunch of other similar macroes that turn into a nightmare.
Yes, I did once define a macro
#define EVER (;;)
but I was much, much younger then.
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#define BYTES *8 JohnF <john@please.see.sig.for.email.com> - 2012-08-28 07:44 +0000
Re: #define BYTES *8 Mark Bluemel <mark_bluemel@pobox.com> - 2012-08-28 09:07 +0100
Re: #define BYTES *8 Keith Thompson <kst-u@mib.org> - 2012-08-28 01:38 -0700
Re: #define BYTES *8 JohnF <john@please.see.sig.for.email.com> - 2012-08-28 09:21 +0000
Re: #define BYTES *8 "BartC" <bc@freeuk.com> - 2012-08-28 12:34 +0100
Re: #define BYTES *8 JohnF <john@please.see.sig.for.email.com> - 2012-08-28 12:23 +0000
Re: #define BYTES *8 Kenneth Brody <kenbrody@spamcop.net> - 2012-08-29 11:10 -0400
Re: #define BYTES *8 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-29 11:36 -0400
Re: #define BYTES *8 Adrian Ratnapala <raka@scooter.fritz.box> - 2012-08-30 04:01 +0000
Re: #define BYTES *8 Kenneth Brody <kenbrody@spamcop.net> - 2012-08-30 19:08 -0400
<OT> Re: #define BYTES *8 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-30 21:30 -0400
Re: <OT> Re: #define BYTES *8 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-31 02:49 +0100
Re: <OT> Re: #define BYTES *8 JohnF <john@please.see.sig.for.email.com> - 2012-08-31 08:32 +0000
Re: <OT> Re: #define BYTES *8 88888 Dihedral <dihedral88888@googlemail.com> - 2012-08-31 03:55 -0700
Re: <OT> Re: #define BYTES *8 "BartC" <bc@freeuk.com> - 2012-08-31 10:58 +0100
Re: <OT> Re: #define BYTES *8 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-31 11:53 +0100
Re: <OT> Re: #define BYTES *8 "BartC" <bc@freeuk.com> - 2012-08-31 12:39 +0100
Re: <OT> Re: #define BYTES *8 Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-31 15:35 +0100
Re: <OT> Re: #define BYTES *8 "BartC" <bc@freeuk.com> - 2012-08-31 19:15 +0100
Re: <OT> Re: #define BYTES *8 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-31 14:39 -0400
Re: <OT> Re: #define BYTES *8 Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-09-06 15:14 +0300
Re: #define BYTES *8 "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2012-08-28 12:24 -0400
Re: #define BYTES *8 "BartC" <bc@freeuk.com> - 2012-08-28 17:44 +0100
Re: #define BYTES *8 Keith Thompson <kst-u@mib.org> - 2012-08-28 14:42 -0700
Re: #define BYTES *8 pete <pfiland@mindspring.com> - 2012-08-28 23:47 -0400
Re: #define BYTES *8 Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-08-29 22:20 -0600
Re: #define BYTES *8 John Bode <jfbode1029@gmail.com> - 2012-09-06 15:32 -0700
Re: #define BYTES *8 pete <pfiland@mindspring.com> - 2012-09-06 20:58 -0400
Re: #define BYTES *8 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-06 21:13 -0400
Re: #define BYTES *8 Öö Tiib <ootiib@hot.ee> - 2012-09-07 03:00 -0700
Re: #define BYTES *8 pete <pfiland@mindspring.com> - 2012-09-08 10:00 -0400
Re: #define BYTES *8 "BartC" <bc@freeuk.com> - 2012-09-07 02:22 +0100
Re: #define BYTES *8 John Bode <jfbode1029@gmail.com> - 2012-09-07 05:55 -0700
Re: #define BYTES *8 Tim Rentsch <txr@alumni.caltech.edu> - 2012-09-07 14:20 -0700
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