Defined in header <uchar.h> | ||
|---|---|---|
size_t mbrtoc32( char32_t restrict * pc32, 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 32-bit wide character representation (but typically, UTF-32).
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 32-bit wide character and stores it in *pc32 (if pc32 is not null).
If the multibyte character in *s corresponds to a multi-char32_t sequence (not possible with UTF-32), then after the first call to this function, *ps is updated in such a way that the next calls to mbrtoc32 will write out the additional char32_t, without considering *s.
If s is a null pointer, the values of n and pc32 are ignored and the call is equivalent to mbrtoc32(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_32__ is defined, the 32-bit encoding used by this function is UTF-32; otherwise, it is implementation-defined. The macro is always defined and the encoding is always UTF-32.(since C23) In any case, the multibyte character encoding used by this function is specified by the currently active C locale.
| pc32 | - | pointer to the location where the resulting 32-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 *pc32 if non-null) was the null character [1...n] of the multibyte character successfully converted from s (size_t)-3 if the next char32_t from a multi-char32_t character has now been written to *pc32. 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 *pc32. (size_t)-1 if encoding error occurs. Nothing is written to *pc32, the value EILSEQ is stored in errno and the value of *ps is unspecified. #include <stdio.h>
#include <locale.h>
#include <string.h>
#include <uchar.h>
#include <assert.h>
int main(void)
{
setlocale(LC_ALL, "en_US.utf8");
char in[] = u8"zĂć°´đ"; // or "z\u00df\u6c34\U0001F34C"
const size_t in_size = sizeof in / sizeof *in;
printf("Processing %zu UTF-8 code units: [ ", in_size);
for (size_t i = 0; i < in_size; ++i)
printf("0x%02x ", (unsigned char)in[i]);
puts("]");
char32_t out[in_size];
char32_t *p_out = out;
char *p_in = in, *end = in + in_size;
mbstate_t state;
memset(&state, 0, sizeof(state));
size_t rc;
while ((rc = mbrtoc32(p_out, p_in, end - p_in, &state)))
{
assert(rc != (size_t)-3); // no surrogate pairs in UTF-32
if (rc == (size_t)-1) break; // invalid input
if (rc == (size_t)-2) break; // truncated input
p_in += rc;
++p_out;
}
size_t out_size = p_out+1 - out;
printf("into %zu UTF-32 code units: [ ", out_size);
for (size_t i = 0; i < out_size; ++i)
printf("0x%08X ", out[i]);
puts("]");
}Output:
Processing 11 UTF-8 code units: [ 0x7a 0xc3 0x9f 0xe6 0xb0 0xb4 0xf0 0x9f 0x8d 0x8c 0x00 ] into 5 UTF-32 code units: [ 0x0000007A 0x000000DF 0x00006C34 0x0001F34C 0x00000000 ]
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(C11) | converts a 32-bit wide character to narrow multibyte string (function) |
C++ documentation for mbrtoc32 |
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