From cppreference.com
std::size_tmbrtowc(wchar_t*pwc,constchar*s,std::size_tn,std::mbstate_t*ps);Converts a narrow multibyte character to a wide character.
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). If the function determines that the next multibyte character in s is complete and valid, converts it to the corresponding wide character and stores it in *pwc (if pwc is not null).
If s is a null pointer, the values of n and pwc are ignored and call is equivalent to std::mbrtowc(nullptr,"",1,ps).
If the wide character produced is the null character, the conversion state stored in *ps is the initial shift state.
Parameters
pwc - pointer to the location where the resulting 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 used when interpreting the multibyte string Return value
The first of the following that applies:
0 if the character converted from s (and stored in pwc if non-null) was the null character.
the number of bytes [1...n] of the multibyte character successfully converted from s.
static_cast<std::size_t>(-2) if the next n bytes constitute an incomplete, but so far valid, multibyte character. Nothing is written to *pwc.
static_cast<std::size_t>(-1) if encoding error occurs. Nothing is written to *pwc, the value
is stored in
and the value of *ps is left unspecified.
Example
Run this code
#include<clocale>#include<cstring>#include<cwchar>#include<iostream>voidprint_mb(constchar*ptr){std::mbstate_tstate=std::mbstate_t();// initial stateconstchar*end=ptr+std::strlen(ptr);intlen;wchar_twc;while((len=std::mbrtowc(&wc,ptr,end-ptr,&state))>0){std::wcout<<"Next "<<len<<" bytes are the character "<<wc<<'\n';ptr+=len;}}intmain(){std::setlocale(LC_ALL,"en_US.utf8");// UTF-8 narrow multibyte encodingconstchar*str="z\u00df\u6c34\U0001d10b";// or u8"zß水𝄋"// or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b";print_mb(str);}Output:
Next 1 bytes are the character z Next 2 bytes are the character ß Next 3 bytes are the character 水 Next 4 bytes are the character 𝄋 See also
converts the next multibyte character to wide character
(function)
converts a wide character to its multibyte representation, given state
(function)
[virtual]
converts a string from ExternT to InternT, such as when reading from file
(virtual protected member function of std::codecvt<InternT,ExternT,StateT>)