Conversion of long type to int type
in [C++]
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From: Goran on 9 Feb 2010 01:47 On Feb 9, 5:07 am, Joseph Bentley <joe.foxho...(a)gmail.com> wrote: > This code produces a warning regarding "conversion of long type to int > type". > ... > void funk(int); > ... > long whatever; > ... > funk(whatever); // warning here > ... > > Of course, I know that I should avoid these situations when I can, > like making funk()'s argument a long. But sometimes funk() is not > your function, and you must live with the int argument. Ok, then, is "long whatever" yours? ;-) > So my > question is, should I suppress the warning, or is there some cast I > don't know about to disguise the problem, some another approach, or > forget about it? Seriously, compiler is telling you that something might be wrong. But it has no idea if that's true and if yes, why - that's your problem. If you just cast, you are telling the compiler "I know that this particular long never has values outside [INT_MIN, INT_MAX]" (but then you might try to use int yourself, not long). If you can't say that, you should take a precautionary step. What would that be, __hugely__ depends on the context. An assert, exception, log-and-continue come to mind as a course of action. There is IMO __no__ easy way out. Goran. -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Sirius Black on 13 Feb 2010 06:23
On Tue, 09 Feb 2010 12:43:53 -0600, Francis Glassborow wrote: <snip> > You might try producing a checking overload of funk to catch cases where > whatever is out of the int range. > > void funk(long value){ > if (value > INT_MAX || value < INT_MIN) throw range_error; return > funk( static_cast<int> value ); > } > > And that return is fine, the standard is carefully crafgted to allow > return of void in cases like this one. Why return? Even without return the behavior is same, is n't it? ~ Sirius -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] |