wctype.h(7POSIX)

💖 wctype.h — the wide-character classification & mapping header, bestie edition 💖

okay so real talk: this is wctype.h(7POSIX) from the POSIX Programmer's Manual, and it's about to be your new obsession. sit down, grab a boba, let's get into it 🧋✨

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🌸 PROLOG 🌸

so like, heads up before we even start:

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.

translation: Linux might do its own lil thing, so check the Linux page too, and maybe this interface isn't even on Linux. no cap, go look 🫶

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✨ NAME ✨

wctype.h — wide-character classification and mapping utilities 💅

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🎀 SYNOPSIS 🎀

#include <wctype.h>

that's it. that's the whole vibe. one include and you're in 👑

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🌈 DESCRIPTION 🌈

okay so some of the stuff on this page is extra — it goes beyond the ISO C standard. if you want those symbols visible in this header, your app shall define the appropriate feature test macro (peep the System Interfaces volume of POSIX.1‐2017, Section 2.2, The Compilation Environment). no macro, no symbols. periodt.

🦋 the types it defines

• wint_t — as described in <wchar.h>.
• wctrans_t — a scalar type that can hold values which represent locale-specific character mappings. it's giving "tiny container for mapping vibes".
• wctype_t — as described in <wchar.h>.

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

💜 the macro it defines

• WEOF — as described in <wchar.h>.

🔥 the one rule you cannot skip

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.

bestie. UNDEFINED. do not pass it anything else. that's not a drill, that's a whole 💀 moment waiting to happen.

the behavior of these functions shall be affected by the LC_CTYPE category of the current locale. yes, locale is the main character here 👑

🌟 a lil side effect

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>. it's generous like that 🫶

🎀 the function squad

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);

look at them all lined up. iconic lineup fr fr 🌈⭐

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🙈 APPLICATION USAGE 🙈

None.

like, literally none. nothing to say. we said what we said 💅

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💭 RATIONALE 💭

None.

also none. the reasoning? vibes only, apparently 🦋

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⭐ FUTURE DIRECTIONS ⭐

None.

nothing planned, nothing changing. stay tuned forever, bestie 🎀

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👑 SEE ALSO 👑

go peek at these:

• <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()

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💜 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 .

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and that's the whole page, bestie 🫶 this was IEEE/The Open Group, 2017 — the wctype.h(7POSIX) energy, served fresh. now go forth and classify some wide characters, you absolute main character 👑💖✨