Can anyone help with a quick query...
I've seen the ASSERT macro defined as:
#define ASSERT(f) \
do { \
if (!(f) && assertFailedOnL ine (THIS_FILE, __LINE__)) \
FatalExit (0); \
} while (0) \
When I comple this in debug mode the compiler warns "conditiona l
expression is constant", because of the while (0). Why is the ASSERT
macro defined this way? The loop only runs once so why not get rid of
the do..while and use:
#define ASSERT(f) \
if (!(f) && assertFailedOnL ine (THIS_FILE, __LINE__)) \
FatalExit (0); \
This also gets rid of the compiler warning.
Is there any reason to use the first definition?
Martin
Nov 13 '05
36  14128 
John Devereux wrote: What is wrong with simply
if(x) y();
???
Syntactically, nothing. In practice, there are two reasons why I don't do
this.
Firstly, when I'm stepping through code with one of those new-fangled
debuggers, it's much easier to see whether y() is called if it's on a
separate line.
Secondly (and this applies equally to the multi-line version of the same
code), Murphy's Law states quite clearly that, if I use a single-statement
if() now, I will inevitably, and probably at some point in the very near
future, think of something else that needs to be done in the same block, so
I might as well make it a compound statement right now.
--
Richard Heathfield : bi****@eton.pow ernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton
Richard Heathfield <do******@addre ss.co.uk.invali d> writes: John Devereux wrote:
What is wrong with simply
if(x) y();
???
Syntactically, nothing. In practice, there are two reasons why I don't do
this.
Firstly, when I'm stepping through code with one of those new-fangled
debuggers, it's much easier to see whether y() is called if it's on a
separate line.
Yes, that's true. Similarly, I suppose your form makes it easier to
locate the offending line when you get a compiler diagnostic.
Secondly (and this applies equally to the multi-line version of the same
code), Murphy's Law states quite clearly that, if I use a single-statement
if() now, I will inevitably, and probably at some point in the very near
future, think of something else that needs to be done in the same block, so
I might as well make it a compound statement right now.
No. Never do today what can be put off until tomorrow :)
--
John Devereux
Richard Heathfield wrote:
.... snip ...
No, the macro isn't the problem. People are the problem. They
/will/ keep turning this:
if(w != x)
y();
into this:
if(w != x)
y();
z();
and then wondering why z() is called more often than they expected.
(Utter foolishness, I know.)
Which is why my compromise, not rigorously adhered to, is:
if (w != x) y();
vs
if (w != x) {
y();
z();
}
This removes the temptation to squeeze in a line somewhere. It
also does not exacerbate the newline shortage.
--
Chuck F (cb********@yah oo.com) (cb********@wor ldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net> USE worldnet address!
CBFalconer wrote: Richard Heathfield wrote:
... snip ...
No, the macro isn't the problem. People are the problem. They
/will/ keep turning this:
if(w != x)
y();
into this:
if(w != x)
y();
z();
and then wondering why z() is called more often than they expected.
(Utter foolishness, I know.)
Which is why my compromise, not rigorously adhered to, is:
if (w != x) y();
vs
if (w != x) {
y();
z();
}
This removes the temptation to squeeze in a line somewhere. It
also does not exacerbate the newline shortage.
No shortage here in the UK. In the interests of cross-pond amity, I present
you with a newline generator:
#include <stdio.h>
{
int i = 0;
while(i++ < 1000)
{
puts("\n\n\n\n\ n\n\n\n\n\n\n\n \n\n\n\n\n\n\n\ n");
}
return 0;
}
You can redirect to a file, of course. If you use them all up, just run it
again.
No charge. God Bless America.
--
Richard Heathfield : bi****@eton.pow ernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton
On Sun, 23 Nov 2003 02:34:01 -0500, Sheldon Simms
<sh**********@y ahoo.com> wrote: I have
never seen a single case in which a programmer actually had any problem
with this style
I have. I don't know how often it happens, because I only see those
cases where the bug doesn't become obvious immediately and I have to
fix it.
--
Al Balmer
Balmer Consulting re************* ***********@att .net
In <vf**********@d evereux.me.uk> John Devereux <jd*@devereux.m e.uk> writes: Richard Heathfield <do******@addre ss.co.uk.invali d> writes:
John Devereux wrote:
What is wrong with simply
if(x) y();
???
Syntactically, nothing. In practice, there are two reasons why I don't do
this.
Firstly, when I'm stepping through code with one of those new-fangled
debuggers, it's much easier to see whether y() is called if it's on a
separate line.
Yes, that's true. Similarly, I suppose your form makes it easier to
locate the offending line when you get a compiler diagnostic.
If this is an issue at all (not everybody is a debugger junkie), there is
a simpler solution:
if (x)
y();
i.e. exactly the way you'd do it if x were a fairly long expression and/or
the y() function had a lot of parameters.
Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de
Richard Heathfield <do******@addre ss.co.uk.invali d> spoke thus: No shortage here in the UK. In the interests of cross-pond amity, I present
you with a newline generator:
(snipped)
You do seem to be short on semicolons however, because apparently you
didn't have enough to both write proper code and supply a winky-face
to indicate that the post was tongue-in-cheek. I'd give you a few,
but unfortunately I don't even have one to winky-face this post, never
mind yours. It seems, then, that we will sound much terser than we
really are, at least until China begins exporting cheap semicolons.
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.
Christopher Benson-Manica <at***@nospam.c yberspace.org> wrote: Richard Heathfield <do******@addre ss.co.uk.invali d> spoke thus:
No shortage here in the UK. In the interests of cross-pond amity, I present
you with a newline generator: (snipped)
<unsnipped>
#include <stdio.h>
{
int i = 0;
while(i++ < 1000)
{
puts("\n\n\n\n\ n\n\n\n\n\n\n\n \n\n\n\n\n\n\n\ n");
}
return 0;
}
You do seem to be short on semicolons however, because apparently you
didn't have enough to both write proper code and supply a winky-face
to indicate that the post was tongue-in-cheek.
As it turns out Richard isn't short on semicolons but on
'int main(void)'s. I can offer him some of my spare ones:
int main(void) int main(void) int main(void) int main(void)
int main(void) int main(void) int main(void) int main(void)
BTW: I still have a whole lot of 'void main(void)'s in a box
in my cellar, left over from my first attempts in writing C
programs; is anybody interested? Free of charge, delivery via
email...
I'd give you a few,
but unfortunately I don't even have one to winky-face this post, never
mind yours. It seems, then, that we will sound much terser than we
really are, at least until China begins exporting cheap semicolons.
Coincidentally I just received a box of brand new premium semicolons
today; here you go:
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
If you need more, just email me. ;-)
--
Irrwahn
(ir*******@free net.de)
Irrwahn Grausewitz <ir*******@free net.de> spoke thus: Coincidentally I just received a box of brand new premium semicolons
today; here you go:
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;
;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;
Great, thanks. My winky faces will look stupdendous now ;)
--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.
On Wed, 26 Nov 2003 15:41:18 +0000 (UTC), Christopher Benson-Manica
<at***@nospam.c yberspace.org> wrote: Richard Heathfield <do******@addre ss.co.uk.invali d> spoke thus:
No shortage here in the UK. In the interests of cross-pond amity, I present
you with a newline generator:
(snipped)
You do seem to be short on semicolons however, because apparently you
didn't have enough to both write proper code and supply a winky-face
to indicate that the post was tongue-in-cheek.
I didn't need a "winky-face" to categorize that post ;-)
--
Al Balmer
Balmer Consulting re************* ***********@att .net This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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