Set character set to multi byte by using code

Is there a way to set the character set to multi byte in code. By that I开发者_StackOverflow mean without going into the properties of the compiler and setting it. I mean it by, well...in code. :p

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look at wcstombs() or perhaps WideCharToMultiByte()

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There are #defines that control how things are compiled:

#define _MBCS