| Functions | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Wide/multibyte conversions | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(C95) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Types | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Macros | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Defined in header <stdlib.h> | ||
int mblen(constchar* s,size_t n); | ||
Determines the size, in bytes, of the multibyte character whose first byte is pointed to bys.
Ifs is a null pointer,resets the global conversion state and(until C23) determined whether shift sequences are used.
This function is equivalent to the callmbtowc((wchar_t*)0, s, n), except that conversion state ofmbtowc is unaffected.
Contents |
| 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 charcter'\0'.
Ifs is a null pointer,resets its internal conversion state to represent the initial shift state and(until C23) 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).
Each call to | (until C23) |
| (since C23) |
#include <locale.h>#include <stdio.h>#include <stdlib.h>#include <string.h> // the number of characters in a multibyte string is the sum of mblen()'s// note: the simpler approach is mbstowcs(NULL, str, sz)size_t strlen_mb(constchar* ptr){size_t result=0;constchar* end= ptr+strlen(ptr); mblen(NULL,0);// reset the conversion statewhile(ptr< end){int next= mblen(ptr, end- ptr);if(next==-1){perror("strlen_mb");break;} ptr+= next;++result;}return result;} void dump_bytes(constchar* str){for(constchar* end= str+strlen(str); str!= end;++str)printf("%02X ",(unsignedchar)str[0]);printf("\n");} int main(void){setlocale(LC_ALL,"en_US.utf8");constchar* str="z\u00df\u6c34\U0001f34c";printf("The string\"%s\" consists of %zu characters, but %zu bytes: ", str, strlen_mb(str),strlen(str)); dump_bytes(str);}
Possible output:
The string "zß水🍌" consists of 4 characters, but 10 bytes: 7A C3 9F E6 B0 B4 F0 9F 8D 8C
| converts the next multibyte character to wide character (function)[edit] | |
(C95) | returns the number of bytes in the next multibyte character, given state (function)[edit] |
C++ documentation formblen | |
