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Message: [QUOTE="James Kuyper, post: 4223729"] His assertion that it "should be forbidden" is somewhat ambiguous. If he's suggesting that you should be forbidden to write that, because it is not permitted in C99, he's wrong. However, he could also be suggesting that, while it is currently permitted, it should not be. If so, then he might be talking about the idea, which has frequently been discussed, that it was a mistake for C to conflate arithmetic and boolean values the way that it does. I tend to agree, but it's not feasible to change that aspect of C without breaking a LOT of code (including most of mine: since C does conflate them, I make heavy use of that fact in my code). To make this idea clearer, let me outline how a new C-like language that implemented this idea would differ from C: * in C, _Bool is a standard unsigned integer type. As such, it is also a member of the several other type categories: "unsigned", "standard", "integer", "basic", "real", "arithmetic", "scalar", and "object". In this new language, _Bool would only be a member of the last two of those type categories. * All relational and equality comparisons result in a _Bool value, even in #if expressions. * All of the following are constrained to be of type _Bool: - The operands of all logical operators (!, &&, ||) - The first operand of ?: - The condition in if(), while() and do while() statements - The condition in #if directives. * There are no conversions, implicit or explicit, permitted between _Bool and other types. The equivalent of converting scalar_value to _Bool can be performed by "scalar_value==0", and the equivalent of conversion from _Bool can be performed by "boolean_value ? 1 : 0". * Values of type _Bool are not implicitly promoted to 'int'. In such a language, a|b would be an error, because bitwise-or requires that it's operands have integer type. If you actually needed to express the same idea, you could write (a?1:0)|(b?1:0), or (a||b)?1:0. Yes, those expressions are clumsier - but that's precisely the point: the increased clumsiness is supposed to make it easier for you to stop and think "does it really make sense to do this?" - the answer will often be "No". The idea is that things which often make sense should be easier to write than things that do not usually make sense. [/QUOTE]

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