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| Wide/multibyte conversions | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Defined in header <stdlib.h> | ||
int mbtowc(wchar_t* pwc,constchar* s,size_t n) | (until C99) | |
int mbtowc(wchar_t*restrict pwc,constchar*restrict s,size_t n) | (since C99) | |
Converts a multibyte character whose first byte is pointed to bys to a wide character, written to*pwc ifpwc is not null.
Ifs is a null pointer, resets the global conversion state and determines whether shift sequences are used.
Contents |
Each call tombtowc updates the internal global conversion state (a static object of typembstate_t, known only to this function). If the multibyte encoding uses shift states, care must be taken to avoid backtracking or multiple scans. In any case, multiple threads should not callmbtowc without synchronization:mbrtowc may be used instead.
| pwc | - | pointer to the wide character for output |
| s | - | pointer to the multibyte character |
| n | - | limit on the number of bytes in s that can be examined |
Ifs is not a null pointer, returns the number of bytes that are contained in the multibyte character or-1 if the first bytes pointed to bys do not form a valid multibyte character or0 ifs is pointing at the null character'\0'.
Ifs is a null pointer, resets its internal conversion state to represent the initial shift state and returns0 if the current multibyte encoding is not state-dependent (does not use shift sequences) or a non-zero value if the current multibyte encoding is state-dependent (uses shift sequences).
#include <locale.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <wchar.h> // print multibyte string to wide-oriented stdout// equivalent to wprintf(L"%s\n", ptr);void print_mb(constchar* ptr){ mbtowc(NULL,NULL,0);// reset the conversion stateconstchar* end= ptr+strlen(ptr);int ret=0;for(wchar_t wc;(ret= mbtowc(&wc, ptr, end- ptr))>0; ptr+= ret)wprintf(L"%lc", wc);wprintf(L"\n");} int main(void){setlocale(LC_ALL,"en_US.utf8");// UTF-8 narrow multibyte encoding print_mb("z\u00df\u6c34\U0001F34C");// or "zß水🍌"}
Output:
zß水🍌
(C95) | converts the next multibyte character to wide character, given state (function)[edit] |
| returns the number of bytes in the next multibyte character (function)[edit] | |
C++ documentation formbtowc | |
