CODEWITHSUNDEEP
c++windows
johndoe
johndoe

Reputation: 303

How to Deal with Varying String types?

I have to work with an API that is using Microsoft's TCHAR macros and such, so I was wondering if I could use C++ in a way to simplify the task. So i was wondering if there is a way to support implicit conversion and why/why not std::string doesn't support converting from a smaller char size:

#include <Windows.h>

using String = std::basic_string<TCHAR>; // say TCHAR = wchar_t or equivalent

String someLiteralString = "my simple ansi string"; // Error here obviously

// some polymorphic class...

    const TCHAR* MyOverriddenFunction() override { return someLiteralString.c_str(); }

// end some polymorphic class

Upvotes: 0

Views: 98

Answers (2)

MHesham
MHesham

Reputation: 41

Use the (ATL/MFC) CStringT class, it will make your life much easier.

http://msdn.microsoft.com/en-us/library/ms174284(v=vs.80).aspx

Upvotes: 0

Mark Ransom
Mark Ransom

Reputation: 308206

The reason implicit conversion isn't supported is that conversion can be complicated. The simple case is when the string to convert is pure ASCII as in your example, but there's no way to guarantee that. The creators of the standard wisely stayed away from that problem.

If you don't know whether your strings are wide-character or not, you can use Microsoft's _T() macro around each string literal to generate the proper characters. But you say you don't want to do that.

Modern Windows programming always uses wide characters in the API. Chances are your program is too, otherwise the code you've shown would not cause an error. It's very unlikely that once you've used wide characters you'll switch back to narrow ones. A simple one-character change to your literals will make them wide-character to match the string type:

String someLiteralString = L"my simple ansi string";

Upvotes: 1

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