The Open Group Base Specifications Issue 8
IEEE Std 1003.1-2024
Copyright © 2001-2024 The IEEE and The Open Group

NAME

wchar.h — wide-character handling

SYNOPSIS

#include <wchar.h>

DESCRIPTION

[CX] [Option Start] Some of the functionality described on this reference page extends the ISO C standard. Applications shall define the appropriate feature test macro (see XSH 2.2 The Compilation Environment ) to enable the visibility of these symbols in this header. [Option End]

The <wchar.h> header shall define the following types:

FILE
[CX] [Option Start] As described in <stdio.h>. [Option End]
locale_t
[CX] [Option Start] As described in <locale.h>. [Option End]
mbstate_t
A complete object type other than an array type that can hold the conversion state information necessary to convert between sequences of (possibly multi-byte) characters and wide characters. [CX] [Option Start]  If a codeset is being used such that an mbstate_t needs to preserve more than two levels of reserved state, the results are unspecified. [Option End]
size_t
As described in <stddef.h>.
va_list
[CX] [Option Start] As described in <stdarg.h>. [Option End]
wchar_t
As described in <stddef.h>.
wint_t
An integer type capable of storing any valid value of wchar_t or WEOF.

The tag tm shall be declared as naming an incomplete structure type, the contents of which are described in the <time.h> header.

The implementation shall support one or more programming environments in which the width of wint_t is no greater than the width of type long. The names of these programming environments can be obtained using the confstr() function or the getconf utility.

The <wchar.h> header shall define the following macros:

WCHAR_MAX
As described in <stdint.h>.
WCHAR_MIN
As described in <stdint.h>.
WEOF
Constant expression of type wint_t that is returned by several WP functions to indicate end-of-file.
NULL
As described in <stddef.h>.

[CX] [Option Start] Inclusion of the <wchar.h> header may make visible all symbols from the headers <ctype.h>, <string.h>, <stdarg.h>, <stddef.h>, <stdio.h>, <stdlib.h>, and <time.h>. [Option End]

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided for use with ISO C standard compilers. Arguments to functions in this list can point to arrays containing wchar_t values that do not correspond to members of the character set of the current locale. Such values shall be processed according to the specified semantics, unless otherwise stated.

wint_t        btowc(int);
wint_t        fgetwc(FILE *);
wchar_t      *fgetws(wchar_t *restrict, int, FILE *restrict);
wint_t        fputwc(wchar_t, FILE *);
int           fputws(const wchar_t *restrict, FILE *restrict);
int           fwide(FILE *, int);
int           fwprintf(FILE *restrict, const wchar_t *restrict, ...);
int           fwscanf(FILE *restrict, const wchar_t *restrict, ...);
wint_t        getwc(FILE *);
wint_t        getwchar(void);
size_t        mbrlen(const char *restrict, size_t, mbstate_t *restrict);
size_t        mbrtowc(wchar_t *restrict, const char *restrict, size_t,
                  mbstate_t *restrict);
int           mbsinit(const mbstate_t *);
[CX][Option Start]
size_t        mbsnrtowcs(wchar_t *restrict, const char **restrict,
                  size_t, size_t, mbstate_t *restrict);
[Option End]
size_t        mbsrtowcs(wchar_t *restrict, const char **restrict, size_t,
                  mbstate_t *restrict);
[CX][Option Start]
FILE         *open_wmemstream(wchar_t **, size_t *);
[Option End]
wint_t        putwc(wchar_t, FILE *);
wint_t        putwchar(wchar_t);
int           swprintf(wchar_t *restrict, size_t,
                  const wchar_t *restrict, ...);
int           swscanf(const wchar_t *restrict,
                  const wchar_t *restrict, ...);
wint_t        ungetwc(wint_t, FILE *);
int           vfwprintf(FILE *restrict, const wchar_t *restrict, va_list);
int           vfwscanf(FILE *restrict, const wchar_t *restrict, va_list);
int           vswprintf(wchar_t *restrict, size_t,
                  const wchar_t *restrict, va_list);
int           vswscanf(const wchar_t *restrict, const wchar_t *restrict,
                  va_list);
int           vwprintf(const wchar_t *restrict, va_list);
int           vwscanf(const wchar_t *restrict, va_list);
[CX][Option Start]
wchar_t      *wcpcpy(wchar_t *restrict, const wchar_t *restrict);
wchar_t      *wcpncpy(wchar_t *restrict, const wchar_t *restrict, size_t);
[Option End]
size_t        wcrtomb(char *restrict, wchar_t, mbstate_t *restrict);
[CX][Option Start]
int           wcscasecmp(const wchar_t *, const wchar_t *);
int           wcscasecmp_l(const wchar_t *, const wchar_t *, locale_t);
[Option End]
wchar_t      *wcscat(wchar_t *restrict, const wchar_t *restrict);
wchar_t      *wcschr(const wchar_t *, wchar_t);
int           wcscmp(const wchar_t *, const wchar_t *);
int           wcscoll(const wchar_t *, const wchar_t *);
[CX][Option Start]
int           wcscoll_l(const wchar_t *, const wchar_t *, locale_t);
[Option End]
wchar_t      *wcscpy(wchar_t *restrict, const wchar_t *restrict);
size_t        wcscspn(const wchar_t *, const wchar_t *);
[CX][Option Start]
wchar_t      *wcsdup(const wchar_t *);
[Option End]
size_t        wcsftime(wchar_t *restrict, size_t,
                  const wchar_t *restrict, const struct tm *restrict);
[CX][Option Start]
size_t        wcslcat(wchar_t *restrict, const wchar_t *restrict,
                  size_t);
size_t        wcslcpy(wchar_t *restrict, const wchar_t *restrict,
                  size_t);
[Option End]
size_t        wcslen(const wchar_t *);
[CX][Option Start]
int           wcsncasecmp(const wchar_t *, const wchar_t *, size_t);
int           wcsncasecmp_l(const wchar_t *, const wchar_t *, size_t,
                  locale_t);
[Option End]
wchar_t      *wcsncat(wchar_t *restrict, const wchar_t *restrict, size_t);
int           wcsncmp(const wchar_t *, const wchar_t *, size_t);
wchar_t      *wcsncpy(wchar_t *restrict, const wchar_t *restrict, size_t);
[CX][Option Start]
size_t        wcsnlen(const wchar_t *, size_t);
size_t        wcsnrtombs(char *restrict, const wchar_t **restrict, size_t,
                  size_t, mbstate_t *restrict);
[Option End]
wchar_t      *wcspbrk(const wchar_t *, const wchar_t *);
wchar_t      *wcsrchr(const wchar_t *, wchar_t);
size_t        wcsrtombs(char *restrict, const wchar_t **restrict,
                  size_t, mbstate_t *restrict);
size_t        wcsspn(const wchar_t *, const wchar_t *);
wchar_t      *wcsstr(const wchar_t *restrict, const wchar_t *restrict);
double        wcstod(const wchar_t *restrict, wchar_t **restrict);
float         wcstof(const wchar_t *restrict, wchar_t **restrict);
wchar_t      *wcstok(wchar_t *restrict, const wchar_t *restrict,
                  wchar_t **restrict);
long          wcstol(const wchar_t *restrict, wchar_t **restrict, int);
long double   wcstold(const wchar_t *restrict, wchar_t **restrict);
long long     wcstoll(const wchar_t *restrict, wchar_t **restrict, int);
unsigned long wcstoul(const wchar_t *restrict, wchar_t **restrict, int);
unsigned long long
              wcstoull(const wchar_t *restrict, wchar_t **restrict, int);
[XSI][Option Start]
int           wcswidth(const wchar_t *, size_t);
[Option End]
size_t        wcsxfrm(wchar_t *restrict, const wchar_t *restrict, size_t);
[CX][Option Start]
size_t        wcsxfrm_l(wchar_t *restrict, const wchar_t *restrict,
                  size_t, locale_t);
[Option End]
int           wctob(wint_t);
[XSI][Option Start]
int           wcwidth(wchar_t);
[Option End]
wchar_t      *wmemchr(const wchar_t *, wchar_t, size_t);
int           wmemcmp(const wchar_t *, const wchar_t *, size_t);
wchar_t      *wmemcpy(wchar_t *restrict, const wchar_t *restrict, size_t);
wchar_t      *wmemmove(wchar_t *, const wchar_t *, size_t);
wchar_t      *wmemset(wchar_t *, wchar_t, size_t);
int           wprintf(const wchar_t *restrict, ...);
int           wscanf(const wchar_t *restrict, ...);

The following sections are informative.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

<ctype.h> , <locale.h> , <stdarg.h> , <stddef.h> , <stdint.h> , <stdio.h> , <stdlib.h> , <string.h> , <time.h> , <wctype.h>

XSH 2.2 The Compilation Environment , btowc , confstr , fgetwc , fgetws , fputwc , fputws , fwide , fwprintf , fwscanf , getwc , getwchar , iswalnum , iswalpha , iswcntrl , iswctype , iswdigit , iswgraph , iswlower , iswprint , iswpunct , iswspace , iswupper , iswxdigit , mbrlen , mbrtowc , mbsinit , mbsrtowcs , open_memstream , putwc , putwchar , towlower , towupper , ungetwc , vfwprintf , vfwscanf , wcrtomb , wcscasecmp , wcscat , wcschr , wcscmp , wcscoll , wcscpy , wcscspn , wcsdup , wcsftime , wcslcat , wcslen , wcsncat , wcsncmp , wcsncpy , wcspbrk , wcsrchr , wcsrtombs , wcsspn , wcsstr , wcstod , wcstok , wcstol , wcstoul , wcswidth , wcsxfrm , wctob , wctype , wcwidth , wmemchr , wmemcmp , wmemcpy , wmemmove , wmemset

XCU getconf

CHANGE HISTORY

First released in Issue 4.

Issue 5

Aligned with the ISO/IEC 9899:1990/Amendment 1:1995 (E).

Issue 6

The Open Group Corrigendum U021/10 is applied. The prototypes for wcswidth() and wcwidth() are marked as extensions.

The Open Group Corrigendum U028/5 is applied, correcting the prototype for the mbsinit() function.

The following changes are made for alignment with the ISO/IEC 9899:1999 standard:

The type wctype_t, the isw*(), to*(), and wctype() functions are marked as XSI extensions.

IEEE Std 1003.1-2001/Cor 1-2002, item XBD/TC1/D6/26 is applied, adding the APPLICATION USAGE section.

Issue 7

The mbsnrtowcs(), open_wmemstream(), wcpcpy(), wcpncpy(), wcscasecmp(), wcsdup(), wcsncasecmp(), wcsnlen(), and wcsnrtombs() functions are added from The Open Group Technical Standard, 2006, Extended API Set Part 1.

The wcscasecmp_l(), wcsncasecmp_l(), wcscoll_l(), and wcsxfrm_l() functions are added from The Open Group Technical Standard, 2006, Extended API Set Part 4.

The wctype_t type, and the isw*(), towlower(), and towupper() functions are marked obsolescent in <wchar.h> since the ISO C standard requires the declarations to be in <wctype.h>.

This reference page is clarified with respect to macros and symbolic constants, and a declaration for the locale_t type is added.

POSIX.1-2008, Technical Corrigendum 1, XBD/TC1-2008/0081 [380] is applied.

POSIX.1-2008, Technical Corrigendum 2, XBD/TC2-2008/0088 [73] is applied.

Issue 8

Austin Group Defect 986 is applied, adding wcslcat() and wcslcpy().

Austin Group Defect 1302 is applied, aligning this header with the ISO/IEC 9899:2018 standard.

Austin Group Defect 1330 is applied, removing obsolescent interfaces.

Austin Group Defect 1352 is applied, changing the APPLICATION USAGE and RATIONALE sections.

End of informative text.

 

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