# wctob

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< c‎ | string‎ | multibyte

Defined in header `<wchar.h>` |  |
int wctob( wint_t c ); |  | (since C95)

Narrows a wide character `c` if its multibyte character equivalent in the initial shift state is a single byte.

This is typically possible for the characters from the ASCII character set, since most multibyte encodings (such as UTF-8) use single bytes to encode those characters.

### Parameters

c | - | wide character to narrow

### Return value

EOF if `c` does not represent a multibyte character with length 1 in initial shift state.

otherwise, the single-byte representation of `c` as unsigned char converted to int

### Example

Run this code

    #include <locale.h>
    #include <wchar.h>
    #include <stdio.h>
    #include <assert.h>

    void try_narrowing(wchar_t c)
    {
        int cn = wctob(c);
        if(cn != EOF)
            printf("%#x narrowed to %#x\n", c, cn);
        else
            printf("%#x could not be narrowed\n", c);
    }

    int main(void)
    {
        char* utf_locale_present = setlocale(LC_ALL, "th_TH.utf8");
        assert(utf_locale_present);
        puts("In Thai UTF-8 locale:");
        try_narrowing(L'a');
        try_narrowing(L'๛');

        char* tis_locale_present = setlocale(LC_ALL, "th_TH.tis620");
        assert(tis_locale_present);
        puts("In Thai TIS-620 locale:");
        try_narrowing(L'a');
        try_narrowing(L'๛');
    }

Possible output:

    In Thai UTF-8 locale:
    0x61 narrowed to 0x61
    0xe5b could not be narrowed
    In Thai TIS-620 locale:
    0x61 narrowed to 0x61
    0xe5b narrowed to 0xfb

### References

- C11 standard (ISO/IEC 9899:2011):

  - 7.29.6.1.2 The wctob function (p: 441)

- C99 standard (ISO/IEC 9899:1999):

  - 7.24.6.1.2 The wctob function (p: 387)

### See also

btowc (C95) | widens a single-byte narrow character to wide character, if possible (function)
C++ documentation for wctob

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