The one reason I can think of is to prevent implicit conversions being applied to the thing being cast. In your example, if you said: bool( “foo” ); then “foo” would be implicitly converted to a string, which would then have the explicit bool conversion you provided applied to it. This is not possible if … Read more
I believe Clang is correct to produce this error: The [temp.inst] section of the C++ standard in paragraph 10 says: If a function template or a member function template specialization is used in a way that involves overload resolution, a declaration of the specialization is implicitly instantiated (14.8.3). Forming the implicit conversion sequence necessary to … Read more
The bolded code is a conversion operator. (AKA cast operator) It gives you a way to convert from your custom INT type to another type (in this case, int) without having to call a special conversion function explicitly. For example, with the convert operator, this code will compile: INT i(1234); int i_2 = i; // … Read more
Some random situations where conversion functions are used and not used follow. First, note that conversion functions are never used to convert to the same class type or to a base class type. Conversion during argument passing Conversion during argument passing will use the rules for copy initialization. These rules just consider any conversion function, … Read more
You do copy initialization, and the candidate functions that are considered to do the conversions in the conversion sequence are conversion functions and converting constructors. These are in your case B(const A&) operator B() Now, that are the way you declare them. Overload resolution abstracts away from that, and transforms each candidate into a list … Read more
Member functions of the form operator TypeName() are conversion operators. They allow objects of the class type to be used as if they were of type TypeName and when they are, they are converted to TypeName using the conversion function. In this particular case, operator bool() allows an object of the class type to be … Read more