HP-UX Reference (11i v1 05/09) - 3 Library Functions A-M (vol 6)

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mbsrtowcs(3C) mbsrtowcs(3C)

NAME

mbsrtowcs() - convert a character string to a wide-character string (restartable)

SYNOPSIS

#include <wchar.h>

size_t mbsrtowcs(wchar_t *dst, const char **src, size_t len,

mbstate_t *ps);

DESCRIPTION

The mbsrtowcs() function converts a sequence of characters, beginning in the conversion state

described by the object pointed to by ps, from the array indirectly pointed to by src into a sequence of

corresponding wide-characters. If dst is not a null pointer, the converted characters are stored into the

array pointed to by dst. Conversion continues up to and including a terminating null character, which is

also stored. Conversion stops early in either of the following cases:

• When a sequence of bytes is encountered that does not from a valid character.

• When len codes have been stored into the array pointed to by dst (and dst is not a null pointer).

Each conversion takes place as if by a call to the

mbrtowc() function.

If dst is not a null pointer, the pointer object pointed to by src is assigned either a null pointer (if conversion

stopped due to reaching a terminating null character) or the address just past the last character converted

(if any). If conversion stopped due to reaching a terminating null character, and if dst is not a null pointer,

the resulting state described is the initial conversion state.

If ps is a null pointer, the

mbsrtowcs() function uses its own internal mbstate_t object, which is initial-

ized 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. The imple-

mentation will behave as if no function deﬁned in this speciﬁcation calls

mbsrtowcs()

EXTERNAL INFLUENCES

locale

The behavior of this function is affected by the

LC_CTYPE category of the current locale.

RETURN VALUE

If the input conversion encounters a sequence of bytes that do not form a valid character, an encoding error

occurs. In this case, the mbsrtowcs() function stores the value of the macro [EILSEQ] in errno and

returns (size_t)-1; the conversion state is undeﬁned. Otherwise, it returns the number of characters suc-

cessfully converted, not including the terminating null (if any).

ERRORS

The

mbsrtowcs() 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

mbsrtowcs() was developed by HP and Mitsubishi Electric Corporation.