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std::mbrlen

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< cpp‎ | string‎ | multibyte

 
 
Strings Bibliothek
Null-terminierte Strings
Original:
Null-terminated strings
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Byte-Strings
Multibyte-Strings
Wide Strings
Classes
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Classes
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basic_string
char_traits
 
Nullterminierten Multibyte Strings
Wide / Multibyte Konvertierungen
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Wide/multibyte conversions
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mbsinit
Types
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Types
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mbstate_t
 
Defined in header <cwchar>
std::size_t mbrlen( const char* s, std::size_t n, std::mbstate_t* ps);
Bestimmt die Größe in Bytes, der Rest des Multibyte-Zeichen, dessen erstes Byte wird durch s hingewiesen, angesichts der aktuellen Konvertierungsstatus ps .
Original:
Determines the size, in bytes, of the remainder of the multibyte character whose first byte is pointed to by s, given the current conversion state ps.
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Diese Funktion entspricht dem Aufruf std::mbrtowc(nullptr, s, n, ps?ps:&internal) für einige versteckte Objekt internal vom Typ std::mbstate_t, außer, dass der Ausdruck ps nur einmal ausgewertet wird .
Original:
This function is equivalent to the call std::mbrtowc(nullptr, s, n, ps?ps:&internal) for some hidden object internal of type std::mbstate_t, except that the expression ps is evaluated only once.
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Inhaltsverzeichnis

[Bearbeiten] Parameter

s -
Zeiger auf ein Element einer Multibyte Zeichenkette
Original:
pointer to an element of a multibyte character string
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n -
Grenze für die Anzahl von Bytes in s, die untersucht werden können
Original:
limit on the number of bytes in s that can be examined
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ps -
Zeiger auf die Variable, die die Umwandlung Zustand
Original:
pointer to the variable holding the conversion state
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[Bearbeiten] Rückgabewert

0 wenn die nächste n oder weniger Bytes die Null-Zeichen abgeschlossen .
Original:
0 if the next n or fewer bytes complete the null character.
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Die Anzahl der Bytes (zwischen 1 und n) ausfüllen, dass ein gültiges Multibyte-Zeichen
Original:
The number of bytes (between 1 and n) that complete a valid multibyte character
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(size_t)-1 wenn die Kodierung Fehler auftritt
Original:
(size_t)-1 if encoding error occurs
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(size_t)-2 wenn die nächsten n bytes Teil eines möglicherweise gültiges Multibyte-Zeichen, die noch unvollständig ist nach Prüfung aller n Byte sind
Original:
(size_t)-2 if the next n bytes are part of a possibly valid multibyte character, which is still incomplete after examining all n bytes
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[Bearbeiten] Beispiel

#include <clocale>
#include <string>
#include <iostream>
#include <cwchar>
 
int main()
{
    // allow mbrlen() to work with UTF-8 multibyte encoding
    std::setlocale(LC_ALL, "en_US.utf8");
    // UTF-8 narrow multibyte encoding
    std::string str = u8"水"; // or u8"\u6c34" or "\xe6\xb0\xb4"
    std::mbstate_t mb = std::mbstate_t();
    int len1 = std::mbrlen(&str[0], 1, &mb);
    if(len1 == -2) {
        std::cout << "The first 1 byte of " << str
                  << " is an incomplete multibyte char (mbrlen returns -2)\n";
    }
    int len2 = std::mbrlen(&str[1], str.size()-1, &mb);
    std::cout << "The remaining " << str.size()-1 << " bytes of " << str
              << " hold " << len2 << " bytes of the multibyte character\n";
    std::cout << "Attempting to call mbrlen() in the middle of " << str
              << " while in initial shift state returns "
              << (int)mbrlen(&str[1], str.size(), &mb) << '\n';
 
}

Output:

The first 1 byte of 水 is an incomplete multibyte char (mbrlen returns -2)
The remaining 2 bytes of 水 hold 2 bytes of the multibyte character
Attempting to call mbrlen() in the middle of 水 while in initial shift state returns -1

[Bearbeiten] Siehe auch

wandelt die nächsten Multibyte Zeichen-Zeichen, gegebenen Zustand
Original:
converts the next multibyte character to wide character, given state
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(Funktion) [edit]
gibt die Anzahl der Bytes in den nächsten Multibyte-Zeichens
Original:
returns the number of bytes in the next multibyte character
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(Funktion) [edit]
[virtuell]
berechnet die Länge der Zeichenfolge, externT durch Umwandlung in gegebenen Internt Puffer verbraucht würde
Original:
calculates the length of the externT string that would be consumed by conversion into given internT buffer
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(virtuellen geschützten Member-Funktion of std::codecvt) [edit]
C documentation for mbrlen