Re: Program crashes when running it outside dev environment

On 08 Jun 2007, Richard Heathfield <rjh@xxxxxxxxxxxxxxx> wrote:

David Tiktin said:

On 08 Jun 2007, Richard Heathfield <rjh@xxxxxxxxxxxxxxx> wrote:

So my suggestions would be:

1) crank up your warning level to the max
2) turn off any extensions you can live without
3) fix every single diagnostic message, and *never* with a cast

I'm with you right up to the last clause. Are you saying you
never actually *need* a cast?

No, there are (rare) occasions when you do need a cast. But I
don't know of any occasion where you *need* a cast AND omitting it
violates a constraint or constitutes a syntax error. So adding a
cast is not the right way to fix a diagnostic message. If the
choice is between adding bad code and putting up with a bad
warning, I'll live with the bad warning.

But now you're changing your advice. You get diagnostics for things
other than constraint violations and syntax errors. On the highest
warning levels, you may well get a diagnostic on code like this:

char * ptr = buffer;
int c;

while ((c = getchar()) != EOF)
{
*ptr++ = c;
}

diag.c(73) : warning C4244: '=' : conversion from 'int ' to 'char ',
possible loss of data

That's with MSVC 6.0 and -W4.

Do you think loss of precision diagnostics are "bad warnings"? (I
don't.) Shouldn't we fix this with a cast?

*ptr++ = (char) c;

If not, what do you suggest? If we do nothing, we'll have to think
about that warning every time we build, because an *actual* loss of
precision is often a serious bug.

Dave

--
D.a.v.i.d T.i.k.t.i.n
t.i.k.t.i.n [at] a.d.v.a.n.c.e.d.r.e.l.a.y [dot] c.o.m
.

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