mbrtowc(3C) mbrtowc(3C)
NAME
mbrtowc() - convert a character to a wide-character code (restartable)
SYNOPSIS
DESCRIPTION
If s is a null pointer, the function is equivalent to the call:
In this case, the values of the arguments pwc and n are ignored.
If s is not a null pointer, the 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 function uses its own internal mbstate_t object, which is initialized at program startup to the initial con-
version state. Otherwise, the mbstate_t object pointed to by ps is used to completely describe the current conversion state of the associ-
ated character sequence.
APPLICATION USAGE
The prototype of this function is available to applications if they are:
a. conformant.
b. Compiled with macro with a value >=500.
c. Compiled with macro with a value >= 200112.
EXTERNAL INFLUENCES
Environment Variables
The behavior of this function is affected by the category of the current locale.
RETURN VALUE
The 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 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, is stored in and the conversion state is undefined.
ERRORS
The function may fail if:
Invalid character sequence is detected.
ps points to an object that contains an invalid conversion state.
WARNINGS
With the exception of ASCII characters, the code values of wide characters (type of are specific to the effective locale specified by the
environment variable. These values may not be compatible 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 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 character 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
was developed by HP and Mitsubishi Electric Corporation.
SEE ALSO
mbsinit(3C), glossary(9).
mbrtowc(3C)