Defined in header <uchar.h> | ||
|---|---|---|
size_t mbrtoc16( char16_t* restrict pc16, const char* restrict s,
size_t n, mbstate_t* restrict ps );
| (since C11) |
Converts a single code point from its narrow multibyte character representation to its variable-length 16-bit wide character representation (typically, UTF-16).
If s is not a null pointer, inspects at most n bytes of the multibyte character string, beginning with the byte pointed to by s to determine the number of bytes necessary to complete the next multibyte character (including any shift sequences, and taking into account the current multibyte conversion state *ps). If the function determines that the next multibyte character in s is complete and valid, converts it to the corresponding 16-bit wide character and stores it in *pc16 (if pc16 is not null).
If the multibyte character in *s corresponds to a multi-char16_t sequence (e.g. a surrogate pair in UTF-16), then after the first call to this function, *ps is updated in such a way that the next call to mbrtoc16 will write out the additional char16_t, without considering *s.
If s is a null pointer, the values of n and pc16 are ignored and the call is equivalent to mbrtoc16(NULL, "", 1, ps).
If the wide character produced is the null character, the conversion state *ps represents the initial shift state.
If the macro __STDC_UTF_16__ is defined, the 16-bit encoding used by this function is UTF-16; otherwise, it is implementation-defined. The macro is always defined and the encoding is always UTF-16.(since C23) In any case, the multibyte character encoding used by this function is specified by the currently active C locale.
| pc16 | - | pointer to the location where the resulting 16-bit wide character will be written |
| s | - | pointer to the multibyte character string used as input |
| n | - | limit on the number of bytes in s that can be examined |
| ps | - | pointer to the conversion state object used when interpreting the multibyte string |
The first of the following that applies:
â0â if the character converted from s (and stored in *pc16 if non-null) was the null character [1...n] of the multibyte character successfully converted from s (size_t)-3 if the next char16_t from a multi-char16_t character (e.g. a surrogate pair) has now been written to *pc16. No bytes are processed from the input in this case. (size_t)-2 if the next n bytes constitute an incomplete, but so far valid, multibyte character. Nothing is written to *pc16. (size_t)-1 if encoding error occurs. Nothing is written to *pc16, the value EILSEQ is stored in errno and the value of *ps is unspecified. #include <locale.h>
#include <stdio.h>
#include <uchar.h>
mbstate_t state;
int main(void)
{
setlocale(LC_ALL, "en_US.utf8");
const char in[] = u8"zĂć°´đ"; // or "z\u00df\u6c34\U0001F34C"
const size_t in_sz = sizeof in / sizeof *in;
printf("Processing %zu UTF-8 code units: [ ", in_sz);
for (size_t n = 0; n < in_sz; ++n)
printf("%#x ", (unsigned char)in[n]);
puts("]");
char16_t out[in_sz];
const char *p_in = in, *end = in + in_sz;
char16_t *p_out = out;
for (size_t rc; (rc = mbrtoc16(p_out, p_in, end - p_in, &state));)
{
if (rc == (size_t)-1) // invalid input
break;
else if(rc == (size_t)-2) // truncated input
break;
else if(rc == (size_t)-3) // UTF-16 high surrogate
p_out += 1;
else
{
p_in += rc;
p_out += 1;
};
}
const size_t out_sz = p_out - out + 1;
printf("into %zu UTF-16 code units: [ ", out_sz);
for (size_t x = 0; x < out_sz; ++x)
printf("%#x ", out[x]);
puts("]");
}Output:
Processing 11 UTF-8 code units: [ 0x7a 0xc3 0x9f 0xe6 0xb0 0xb4 0xf0 0x9f 0x8d 0x8c 0 ] into 6 UTF-16 code units: [ 0x7a 0xdf 0x6c34 0xd83c 0xdf4c 0 ]
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(C11) | converts a 16-bit wide character to narrow multibyte string (function) |
C++ documentation for mbrtoc16 |
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