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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