HP-UX Reference (11i v1 00/12) - 3 Library Functions A-M (vol 6)
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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/!!!intro.3c
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m
mbrtowc(3C) mbrtowc(3C)
NAME
mbrtowc() - convert a character to a wide-character code (restartable)
SYNOPSIS
#include <wchar.h>
size_t mbrtowc(wchar_t *pwc, const char *s, size_t n, mbstate_t *ps);
DESCRIPTION
If s is a null pointer, the mbrtowc() function is equivalentto the call:
mbrtowc(NULL, "", 1, ps)
In this case, the values of the arguments pwc and n are ignored.
If s is not a null pointer, the mbrtowc() function inspects at most n bytes beginning at the byte pointed
to by s to determine the number of bytes needed to complete the next character (including any shift
sequences). If the function determines that the next character is completed, it determines the value of the
corresponding wide-character and then, if pwc is not a null pointer, stores that value in the object pointed
to by pwc. If the corresponding wide-character is the null wide-character, the resulting state described is
the initial conversion state.
If ps is a null pointer, the mbrtowc() function uses its own internal mbstate_t object, which is initialized
at program startup to the initial conversion state. Otherwise, the mbstate_t object pointed to by ps is used
to completely describe the current conversion state of the associated character sequence.
EXTERNAL INFLUENCES
locale
The behavior of this function is affected by the
LC_CTYPE category of the current locale.
RETURN VALUE
The mbrtowc() function returns the first of the following that applies:
0 If the next n or fewer bytes complete the character that corresponds to the null wide-
character (which is the value stored).
Positive If the next n or fewer bytes complete a valid character (which is the value stored); the
value returned is the number of bytes that complete the character.
(size_t)-2 If the next n bytes contribute to an incomplete but potentially valid character, and all
n bytes have been processed (no value is stored). When n has at least the value of the
MB_CUR_MAX macro, this case can only occur if s points at a sequence of redundant
shift sequences (for implementations with state-dependent encodings).
(size_t)-1 If an encoding error occurs, in which case the next n or fewer bytes do not contribute
to a complete and valid character (no value is stored). In this case,
EILSEQ is stored
in errno and the conversion state is undefined.
ERRORS
The mbrtowc() function may fail if:
[EINVAL] ps points to an object that contains an invalid conversion state.
[EILSEQ] Invalid character sequence is detected.
WARNINGS
With the exception of ASCII characters, the code values of wide characters (type of wchar_t) are specific
to the effective locale specified by the
LC_CTYPE environment variable. These values may not be compa-
tible with values obtained by specifying other locales that are supported now, or which may be supported in
the future. It is recommended that wide character constants and wide string literals (see the C Reference
Manual) not be used, and that wide character code values not be stored in files or devices because future
standards may dictate changes in the code value assignments of the wide characters. However, wide char-
acter constants and wide string literals corresponding to the characters of the ASCII code set can be safely
used since their values are guaranteed to be the same as their ASCII code set values.
AUTHOR
mbrtowc() was developed by HP and MitsubishiElectric Corporation.
Section 3−−512 − 1 − HP-UX Release 11i: December 2000
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