Can pass string literal for template parameter C Non Visual C Issues Question

Question Can pass string literal for template parameter ( CodeGuru Forums C++ (Non Visual C++ Issues) )
Updated: 2008-08-12 07:15:11 (3)

Can pass string literal for template parameter

Hi

I'm gonna implement a dynamic type-cast mechanism. I need to give unique ID to all classes, and I think hash value calculated from the name of class would be appropriate.

What I'd like to do is something like this:

Code:

template <char const* const psz>
struct _hash_
{
	enum {
		value = *psz
			? (_hash_<psz+1>::value << 2) | *psz
			: 0
	};
};


.........

enum {
	_classid = _hash_<"cMyClass">::value
};

It produces compile errors. I can imagine the reason, (I'm afraid this is fairly stupid idea :S) but I'd like to know if there's any way around.

Thanks in advance

Answers: Can pass string literal for template parameter ( CodeGuru Forums C++ (Non Visual C++ Issues) )

Can pass string literal for template parameter

Quote:

Originally Posted by muse1987

Hi

I'm gonna implement a dynamic type-cast mechanism. I need to give unique ID to all classes, and I think hash value calculated from the name of class would be appropriate.

You have typeid() to get you a compiler-defined name for your classes.

Regards,

Paul McKenzie

Paul McKenzie

Can pass string literal for template parameter

Code:


template <char const* const psz>
struct _hash_
{
	enum {
		value = *psz
			? (_hash_<psz+1>::value << 2) | *psz
			: 0
	};
};

Should be :

Code:


template <const char const*  psz>

I hope this help.

Peter_APIIT

Can pass string literal for template parameter

Why don't you make the struct _hash_ as a function that takes a const char*? And no, you cannot templatize on string literals.

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