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wctype.h - Man Page

wide-character classification and mapping utilities


This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.


#include <wctype.h>


Some of the functionality described on this reference page extends the ISO C standard. Applications shall define the appropriate feature test macro (see the System Interfaces volume of POSIX.1-2017, Section 2.2, The Compilation Environment) to enable the visibility of these symbols in this header.

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


As described in <wchar.h>.


A scalar type that can hold values which represent locale-specific character mappings.


As described in <wchar.h>.

The <wctype.h> header shall define the locale_t type as described in <locale.h>.

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


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.

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>.

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

The following sections are informative.

Application Usage




Future Directions


See Also

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

The System Interfaces volume of POSIX.1-2017, Section 2.2, The Compilation Environment, iswalnum(), iswalpha(), iswblank(), iswcntrl(), iswctype(), iswdigit(), iswgraph(), iswlower(), iswprint(), iswpunct(), iswspace(), iswupper(), iswxdigit(), setlocale(), towctrans(), towlower(), towupper(), wctrans(), wctype()

Referenced By

iswalnum(3p), iswalpha(3p), iswblank(3p), iswcntrl(3p), iswctype(3p), iswdigit(3p), iswgraph(3p), iswlower(3p), iswprint(3p), iswpunct(3p), iswspace(3p), iswupper(3p), iswxdigit(3p), towctrans(3p), towlower(3p), towupper(3p), unistd.h(0p), wchar.h(0p), wctrans(3p), wctype(3p).

2017 IEEE/The Open Group POSIX Programmer's Manual