From cppreference.com
< 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.


[edit] Parameters

c - wide character to narrow

[edit] 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

[edit] Example

#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);
        printf("%#x could not be narrowed\n", c);
int main(void)
    char* utf_locale_present = setlocale(LC_ALL, "th_TH.utf8");
    puts("In Thai UTF-8 locale:");
    char* tis_locale_present = setlocale(LC_ALL, "th_TH.tis620");
    puts("In Thai TIS-620 locale:");

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

[edit] References

  • C11 standard (ISO/IEC 9899:2011):
  • The wctob function (p: 441)
  • C99 standard (ISO/IEC 9899:1999):
  • The wctob function (p: 387)

[edit] See also

widens a single-byte narrow character to wide character, if possible
C++ documentation for wctob