multibyte(3) [osx man page]
MULTIBYTE(3) BSD Library Functions Manual MULTIBYTE(3) NAME
multibyte -- multibyte and wide character manipulation functions LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <limits.h> #include <stdlib.h> #include <wchar.h> DESCRIPTION
The basic elements of some written natural languages, such as Chinese, cannot be represented uniquely with single C chars. The C standard supports two different ways of dealing with extended natural language encodings: wide characters and multibyte characters. Wide characters are an internal representation which allows each basic element to map to a single object of type wchar_t. Multibyte characters are used for input and output and code each basic element as a sequence of C chars. Individual basic elements may map into one or more (up to MB_LEN_MAX) bytes in a multibyte character. The current locale (setlocale(3)) governs the interpretation of wide and multibyte characters. The locale category LC_CTYPE specifically controls this interpretation. The wchar_t type is wide enough to hold the largest value in the wide character representations for all locales. Multibyte strings may contain 'shift' indicators to switch to and from particular modes within the given representation. If explicit bytes are used to signal shifting, these are not recognized as separate characters but are lumped with a neighboring character. There is always a distinguished 'initial' shift state. Some functions (e.g., mblen(3), mbtowc(3) and wctomb(3)) maintain static shift state internally, whereas others store it in an mbstate_t object passed by the caller. Shift states are undefined after a call to setlocale(3) with the LC_CTYPE or LC_ALL categories. For convenience in processing, the wide character with value 0 (the null wide character) is recognized as the wide character string termina- tor, and the character with value 0 (the null byte) is recognized as the multibyte character string terminator. Null bytes are not permitted within multibyte characters. The C library provides the following functions for dealing with multibyte characters: Function Description mblen(3) get number of bytes in a character mbrlen(3) get number of bytes in a character (restartable) mbrtowc(3) convert a character to a wide-character code (restartable) mbsrtowcs(3) convert a character string to a wide-character string (restartable) mbstowcs(3) convert a character string to a wide-character string mbtowc(3) convert a character to a wide-character code wcrtomb(3) convert a wide-character code to a character (restartable) wcstombs(3) convert a wide-character string to a character string wcsrtombs(3) convert a wide-character string to a character string (restartable) wctomb(3) convert a wide-character code to a character SEE ALSO
mklocale(1), setlocale(3), stdio(3), big5(5), euc(5), gb18030(5), gb2312(5), gbk(5), mskanji(5), utf8(5) STANDARDS
These functions conform to ISO/IEC 9899:1999 (``ISO C99''). BSD
April 8, 2004 BSD
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mbstowcs(3) Library Functions Manual mbstowcs(3) NAME
mbstowcs, mbsrtowcs - Converts a multibyte character string to a wide-character string LIBRARY
Standard C Library (libc) SYNOPSIS
#include <stdlib.h> size_t mbstowcs( wchar_t *pwcs, const char *s, size_t n); #include <wchar.h> size_t mbsrtowcs( wchar_t *pwcs, const char **s, size_t n, mbstate_t *ps ); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: mbstowcs(), mbsrtowcs(): XSH5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Points to the array where the result of the conversion is stored. Points or indirectly points to the multibyte-character string to be con- verted. Specifies the number of wide characters in the destination array. Points to an mbstate_t structure containing the conversion state of the data in s. DESCRIPTION
The mbstowcs() function converts a multibyte-character string into a wide-character string, which is stored at a specified location. The function does not examine or convert any characters that follow a null byte, which is converted and stored as a wide-character code with value zero. The function does not store more than n wide characters in pwcs. When operating on overlapping strings, the behavior of this function is undefined. Behavior of the mbstowcs() function is affected by the LC_CTYPE category of the current locale. In locales that use shift-state encoding, the array pointed to by the s parameter begins in the initial shift state. The mbsrtowcs() function is a restartable version of mbstowcs(). Restartable conversion functions obtain and store the conversion state in an mbstate_t structure that can be read and changed by subsequent calls to the same or other restartable conversion functions. RESTRICTIONS
[Tru64 UNIX] The mbsrtowcs() and other restartable versions of conversion functions are functional only when used with locales that sup- port shift-state encoding. Currently, the operating system does not provide any locales that support shift-state encoding, so the mbstowcs() and mbsrtowcs() functions do not differ in terms of run-time behavior. RETURN VALUES
When the mbstowcs() and mbsrtowcs() functions encounter an invalid multibyte character during conversion, they return a value of -1 cast to size_t and set errno to indicate the error. Otherwise: The mbstowcs() function returns the number of characters stored in the output array (or required if pwcs is null), not including a terminating null wide character, if any. When the return value is n, the output array is not null-terminated. The mbsrtowcs() function returns the number of characters stored in the output array, not including a terminating null wide character, if any. ERRORS
If the following condition occurs, the mbstowcs() and mbsrtowcs() functions set errno to the corresponding value: The s parameter contains an invalid multibyte character. RELATED INFORMATION
Functions: btowc(3), mblen(3), mbsinit(3), mbtowc(3), wcstombs(3), wcslen(3), wctob(3), wctomb(3) delim off mbstowcs(3)