Convert wchar_t to char

Question

I was wondering is it safe to do so?

wchar_t wide = /* something */;
assert(wide >= 0 && wide < 256 &&);
char myChar = static_cast

        

Answer 1

Why not just use a library routine wcstombs.

Answer 2

Here's another way of doing it, remember to use free() on the result.

char* wchar_to_char(const wchar_t* pwchar)
{
    // get the number of characters in the string.
    int currentCharIndex = 0;
    char currentChar = pwchar[currentCharIndex];

    while (currentChar != '\0')
    {
        currentCharIndex++;
        currentChar = pwchar[currentCharIndex];
    }

    const int charCount = currentCharIndex + 1;

    // allocate a new block of memory size char (1 byte) instead of wide char (2 bytes)
    char* filePathC = (char*)malloc(sizeof(char) * charCount);

    for (int i = 0; i < charCount; i++)
    {
        // convert to char (1 byte)
        char character = pwchar[i];

        *filePathC = character;

        filePathC += sizeof(char);

    }
    filePathC += '\0';

    filePathC -= (sizeof(char) * charCount);

    return filePathC;
}

Answer 3

Technically, 'char' could have the same range as either 'signed char' or 'unsigned char'. For the unsigned characters, your range is correct; theoretically, for signed characters, your condition is wrong. In practice, very few compilers will object - and the result will be the same.

Nitpick: the last && in the assert is a syntax error.

Whether the assertion is appropriate depends on whether you can afford to crash when the code gets to the customer, and what you could or should do if the assertion condition is violated but the assertion is not compiled into the code. For debug work, it seems fine, but you might want an active test after it for run-time checking too.