MBTOWCSection: Linux Programmer's Manual (3)
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NAMEmbtowc - convert a multibyte sequence to a wide character
#include <stdlib.h> int mbtowc(wchar_t *pwc, const char *s, size_t n);
DESCRIPTIONThe main case for this function is when s is not NULL and pwc is not NULL. In this case, the mbtowc() function inspects at most n bytes of the multibyte string starting at s, extracts the next complete multibyte character, converts it to a wide character and stores it at *pwc. It updates an internal shift state only known to the mbtowc function. If s does not point to a '\0' byte, it returns the number of bytes that were consumed from s, otherwise it returns 0.
If the n bytes starting at s do not contain a complete multibyte character, or if they contain an invalid multibyte sequence, mbtowc() returns -1. This can happen even if n >= MB_CUR_MAX, if the multibyte string contains redundant shift sequences.
A different case is when s is not NULL but pwc is NULL. In this case the mbtowc() function behaves as above, except that it does not store the converted wide character in memory.
A third case is when s is NULL. In this case, pwc and n are ignored. The mbtowc() function resets the shift state, only known to this function, to the initial state, and returns non-zero if the encoding has nontrivial shift state, or zero if the encoding is stateless.
RETURN VALUEIf s is not NULL, the mbtowc() function returns the number of consumed bytes starting at s, or 0 if s points to a null byte, or -1 upon failure.
NOTESThe behavior of mbtowc() depends on the LC_CTYPE category of the current locale.
This function is not multithread safe. The function mbrtowc(3) provides a better interface to the same functionality.
SEE ALSOMB_CUR_MAX(3), mbrtowc(3), mbstowcs(3)
COLOPHONThis page is part of release 3.21 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.