wchar.h(7POSIX)

💖 PROLOG 💖

okay bestie, real talk before we even start: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (so like, go check the corresponding Linux manual page for the tea on Linux behavior), or the interface might not even be implemented on Linux at all. 🙈 No cap.

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✨ NAME ✨

wchar.h — wide-character handling 🦋

so this is the POSIX page for it, iykyk.

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🌸 SYNOPSIS 🌸

#include <wchar.h>

that's it. that's the whole vibe. 💅

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👑 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. slay, but you gotta opt in first. ✨

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

• FILE — as described in <stdio.h>. classic.
• 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. 🫶 And listen: 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. so don't do that bestie.
• 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. (so it's giving "trust me, the details live elsewhere" 😭)

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. the ultimate "we're done here" energy. 💀
• 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>. lowkey a package deal.

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. (aka: not the rules, just the lore 💜)

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🎀 APPLICATION USAGE 🎀

okay so storytime: 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. not deprecated-deprecated yet but like… it's on notice bestie. 💀

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🌈 RATIONALE 🌈

In the ISO C standard, the symbols referenced as XSI extensions are in <wctype.h>. Their presence here is thus an extension. that's the whole reason. periodt. ✨

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🦋 FUTURE DIRECTIONS 🦋

None. 🎀 (iconic of them honestly — nothing coming, we're done here)

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💜 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 💅

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💖 COPYRIGHT 💖

okay bestie, legal era, but make it cute 🎀 — a big chunk of this text got reprinted and reproduced in electronic form, and here's exactly where it came 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

fr fr, if this version and the original IEEE / The Open Group Standard ever disagree on literally anything, the original IEEE and The Open Group Standard is the referee document. it's giving final boss of accuracy. 👑

and if you wanna read the source of truth yourself, the original Standard can be obtained online at http://www.opengroup.org/unix/online.html — go get it, it's iconic ✨

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🫶 any typos tho?

so… any typographical or formatting errors that show up in this page are most likely to have been introduced during the conversion of the source files to man page format. not a vibe, but we move. 💅

to report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html — please do, we're obsessed with fixing things around here 🌸

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and that's a wrap on wchar.h(7POSIX), bestie 🦋 huge slay, wide-character justice served. this one's from IEEE/The Open Group, 2017 — go off, drink some water, and may all your multibyte conversions be correct 💖✨💜