| Localization library | |||||||||||||||||||||||||
| Regular expressions library(C++11) | |||||||||||||||||||||||||
| Formatting library(C++20) | |||||||||||||||||||||||||
| Null-terminated sequence utilities | |||||||||||||||||||||||||
| Byte strings | |||||||||||||||||||||||||
| Multibyte strings | |||||||||||||||||||||||||
| Wide strings | |||||||||||||||||||||||||
| Primitive numeric conversions | |||||||||||||||||||||||||
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| Text encoding identifications | |||||||||||||||||||||||||
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Defined in header <cstdlib> | ||
int mbtowc(wchar_t* pwc,constchar* s,std::size_t n); | ||
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 |
| s | - | pointer to the multibyte character |
| n | - | limit on the number of bytes in s that can be examined |
| pwc | - | pointer to the wide character for output |
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).
Each call tombtowc updates the internal global conversion state (a static object of typestd::mbstate_t, only known 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:std::mbrtowc may be used instead.
#include <clocale>#include <cstdlib>#include <cstring>#include <iostream> int print_mb(constchar* ptr){ std::mbtowc(nullptr,0,0);// reset the conversion stateconstchar* end= ptr+std::strlen(ptr);int ret{};for(wchar_t wc;(ret= std::mbtowc(&wc, ptr, end- ptr))>0; ptr+= ret)std::wcout<< wc;std::wcout<<'\n';return ret;} int main(){std::setlocale(LC_ALL,"en_US.utf8");// UTF-8 narrow multibyte encodingconstchar* str="z\u00df\u6c34\U0001d10b";// or "zß水𝄋"// or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b"; print_mb(str);}
Output:
zß水𝄋
| converts the next multibyte character to wide character, given state (function)[edit] | |
| returns the number of bytes in the next multibyte character (function)[edit] | |
[virtual] | converts a string fromExternT toInternT, such as when reading from file(virtual protected member function of std::codecvt<InternT,ExternT,StateT>)[edit] |
C documentation formbtowc | |
