btowc - cppreference.com (original) (raw)
| | | | | ----------------------- | | ----------- | | 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.
[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] References
C11 standard (ISO/IEC 9899:2011):
7.29.6.1.1 The btowc function (p: 441)
C99 standard (ISO/IEC 9899:1999):
7.24.6.1.1 The btowc function (p: 387)