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

NAME

wctype.h — wide-character classification and mapping utilities

SYNOPSIS

#include <wctype.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 <wctype.h> header shall define the following types:

wint_t
As described in <wchar.h>.
wctrans_t
A scalar type that can hold values which represent locale-specific character mappings.
wctype_t
A scalar type of a data object that can hold values which represent locale-specific character classification.

[CX] [Option Start] The <wctype.h> header shall define the locale_t type as described in <locale.h>. [Option End]

The <wctype.h> header shall define the following macro:

WEOF
As described in <wchar.h>.

For all functions described in this header that accept an argument of type wint_t, the value is representable as a wchar_t or equals the value of WEOF. If this argument has any other value, the behavior is undefined.

The behavior of these functions shall be affected by the LC_CTYPE category of the current locale.

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

int       iswalnum(wint_t);
[CX][Option Start]
int       iswalnum_l(wint_t, locale_t);
[Option End]
int       iswalpha(wint_t);
[CX][Option Start]
int       iswalpha_l(wint_t, locale_t);
[Option End]
int       iswblank(wint_t);
[CX][Option Start]
int       iswblank_l(wint_t, locale_t);
[Option End]
int       iswcntrl(wint_t);
[CX][Option Start]
int       iswcntrl_l(wint_t, locale_t);
[Option End]
int       iswctype(wint_t, wctype_t);
[CX][Option Start]
int       iswctype_l(wint_t, wctype_t, locale_t);
[Option End]
int       iswdigit(wint_t);
[CX][Option Start]
int       iswdigit_l(wint_t, locale_t);
[Option End]
int       iswgraph(wint_t);
[CX][Option Start]
int       iswgraph_l(wint_t, locale_t);
[Option End]
int       iswlower(wint_t);
[CX][Option Start]
int       iswlower_l(wint_t, locale_t);
[Option End]
int       iswprint(wint_t);
[CX][Option Start]
int       iswprint_l(wint_t, locale_t);
[Option End]
int       iswpunct(wint_t);
[CX][Option Start]
int       iswpunct_l(wint_t, locale_t);
[Option End]
int       iswspace(wint_t);
[CX][Option Start]
int       iswspace_l(wint_t, locale_t);
[Option End]
int       iswupper(wint_t);
[CX][Option Start]
int       iswupper_l(wint_t, locale_t);
[Option End]
int       iswxdigit(wint_t);
[CX][Option Start]
int       iswxdigit_l(wint_t, locale_t);
[Option End]
wint_t    towctrans(wint_t, wctrans_t);
[CX][Option Start]
wint_t    towctrans_l(wint_t, wctrans_t, locale_t);
[Option End]
wint_t    towlower(wint_t);
[CX][Option Start]
wint_t    towlower_l(wint_t, locale_t);
[Option End]
wint_t    towupper(wint_t);
[CX][Option Start]
wint_t    towupper_l(wint_t, locale_t);
[Option End]
wctrans_t wctrans(const char *);
[CX][Option Start]
wctrans_t wctrans_l(const char *, locale_t);
[Option End]
wctype_t  wctype(const char *);
[CX][Option Start]
wctype_t  wctype_l(const char *, locale_t);
[Option End]

The following sections are informative.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

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

XSH 2.2 The Compilation Environment , iswalnum , iswalpha , iswblank , iswcntrl , iswctype , iswdigit , iswgraph , iswlower , iswprint , iswpunct , iswspace , iswupper , iswxdigit , setlocale , towctrans , towlower , towupper , wctrans , wctype

CHANGE HISTORY

First released in Issue 5. Derived from the ISO/IEC 9899:1990/Amendment 1:1995 (E).

Issue 6

The iswblank() function is added for alignment with the ISO/IEC 9899:1999 standard.

Issue 7

SD5-XBD-ERN-6 is applied.

The *_l() functions are added from The Open Group Technical Standard, 2006, Extended API Set Part 4.

This reference page is clarified with respect to macros and symbolic constants.

Issue 8

Austin Group Defect 1330 is applied, moving the description of wctype_t from <wchar.h> to <wctype.h>.

End of informative text.

 

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