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PROLOG

       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.

NAME

       wchar.h — wide-character handling

SYNOPSIS

       #include <wchar.h>

DESCRIPTION

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

       FILE        As described in <stdio.h>.

       locale_t    As described in <locale.h>.

       mbstate_t   An 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.  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.

       size_t      As described in <stddef.h>.

       va_list     As described in <stdarg.h>.

       wchar_t     As described in <stddef.h>.

       wctype_t    A scalar type of a data object that can hold values  which  represent  locale-
                   specific character classification.

       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>.

       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>.

       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);
           int           iswalnum(wint_t);
           int           iswalpha(wint_t);
           int           iswcntrl(wint_t);
           int           iswctype(wint_t, wctype_t);
           int           iswdigit(wint_t);
           int           iswgraph(wint_t);
           int           iswlower(wint_t);
           int           iswprint(wint_t);
           int           iswpunct(wint_t);
           int           iswspace(wint_t);
           int           iswupper(wint_t);
           int           iswxdigit(wint_t);
           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 *);
           size_t        mbsnrtowcs(wchar_t *restrict, const char **restrict,
                             size_t, size_t, mbstate_t *restrict);
           size_t        mbsrtowcs(wchar_t *restrict, const char **restrict, size_t,
                             mbstate_t *restrict);
           FILE         *open_wmemstream(wchar_t **, size_t *);
           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        towlower(wint_t);
           wint_t        towupper(wint_t);
           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);
           wchar_t      *wcpcpy(wchar_t *restrict, const wchar_t *restrict);
           wchar_t      *wcpncpy(wchar_t *restrict, const wchar_t *restrict, size_t);
           size_t        wcrtomb(char *restrict, wchar_t, mbstate_t *restrict);
           int           wcscasecmp(const wchar_t *, const wchar_t *);
           int           wcscasecmp_l(const wchar_t *, const wchar_t *, locale_t);
           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 *);
           int           wcscoll_l(const wchar_t *, const wchar_t *, locale_t);
           wchar_t      *wcscpy(wchar_t *restrict, const wchar_t *restrict);
           size_t        wcscspn(const wchar_t *, const wchar_t *);
           wchar_t      *wcsdup(const wchar_t *);
           size_t        wcsftime(wchar_t *restrict, size_t,
                             const wchar_t *restrict, const struct tm *restrict);
           size_t        wcslen(const wchar_t *);
           int           wcsncasecmp(const wchar_t *, const wchar_t *, size_t);
           int           wcsncasecmp_l(const wchar_t *, const wchar_t *, size_t,
                             locale_t);
           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);
           size_t        wcsnlen(const wchar_t *, size_t);
           size_t        wcsnrtombs(char *restrict, const wchar_t **restrict, size_t,
                             size_t, mbstate_t *restrict);
           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);
           int           wcswidth(const wchar_t *, size_t);
           size_t        wcsxfrm(wchar_t *restrict, const wchar_t *restrict, size_t);
           size_t        wcsxfrm_l(wchar_t *restrict, const wchar_t *restrict,
                             size_t, locale_t);
           int           wctob(wint_t);
           wctype_t      wctype(const char *);
           int           wcwidth(wchar_t);
           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

       The iswblank() function was a late addition to the ISO C standard and  was  introduced  at
       the  same  time  as  the  ISO C  standard introduced <wctype.h>, which contains all of the
       isw*() functions. The Open Group Base Specifications had previously aligned with  the  MSE
       working  draft  and  had  introduced the rest of the isw*() functions into <wchar.h>.  For
       backwards-compatibility, the original set of isw*()  functions,  without  iswblank(),  are
       permitted (as part of the XSI option) in <wchar.h>.  For maximum portability, applications
       should include <wctype.h> in order to obtain declarations for the isw*()  functions.  This
       compatibility has been made obsolescent.

RATIONALE

       In  the ISO C standard, the symbols referenced as XSI extensions are in <wctype.h>.  Their
       presence here is thus an extension.

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>

       The System Interfaces volume of POSIX.1‐2017, Section 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(), wcslen(), wcsncat(), wcsncmp(), wcsncpy(), wcspbrk(), wcsrchr(), wcsrtombs(),
       wcsspn(), wcsstr(), wcstod(), wcstok(), wcstol(), wcstoul(), wcswidth(), wcsxfrm(),
       wctob(), wctype(), wcwidth(), wmemchr(), wmemcmp(), wmemcpy(), wmemmove(), wmemset()

       The Shell and Utilities volume of POSIX.1‐2017, getconf

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  by
       the  Institute  of  Electrical  and Electronics Engineers, Inc and The Open Group.  In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .