Namespaces
Variants
Views
Actions

btowc

From cppreference.com
< c‎ | string‎ | multibyte
Defined in header <wchar.h>
wint_t btowc( int c );
(since C95)

Widens a single-byte character c (reinterpreted as unsigned char) to its wide character equivalent.

Most multibyte character encodings use single-byte codes to represent the characters from the ASCII character set. This function may be used to convert such characters to wchar_t.

Contents

[edit] Parameters

c - single-byte character to widen

[edit] Return value

WEOF if c is EOF

wide character representation of c if (unsigned char)c is a valid single-byte character in the initial shift state, WEOF otherwise.

[edit] Example

#include <stdio.h>
#include <wchar.h>
#include <locale.h>
#include <assert.h>
 
void try_widen(unsigned char c)
{
    wint_t w = btowc(c);
    if(w != WEOF)
        printf("The single-byte character %#x widens to %#x\n", c, w);
    else
        printf("The single-byte character %#x failed to widen\n", c);
}
 
int main(void)
{
    char *loc = setlocale(LC_ALL, "lt_LT.iso88594");
    assert(loc);
    printf("In Lithuanian ISO-8859-4 locale:\n");
    try_widen('A');
    try_widen('\xdf'); // German letter ß (U+00df) in ISO-8859-4
    try_widen('\xf9'); // Lithuanian letter ų (U+0173) in ISO-8859-4
 
    setlocale(LC_ALL, "lt_LT.utf8");
    printf("In Lithuanian UTF-8 locale:\n");
    try_widen('A');
    try_widen('\xdf');
    try_widen('\xf9');
}

Possible output:

In Lithuanian ISO-8859-4 locale:
The single-byte character 0x41 widens to 0x41
The single-byte character 0xdf widens to 0xdf
The single-byte character 0xf9 widens to 0x173
In Lithuanian UTF-8 locale:
The single-byte character 0x41 widens to 0x41
The single-byte character 0xdf failed to widen
The single-byte character 0xf9 failed to widen

[edit] See also

(C95)
narrows a wide character to a single-byte narrow character, if possible
(function) [edit]