WCTRANS(3POSIX)

💖 WCTRANS(3POSIX) 💖

okay bestie, welcome to the POSIX Programmer's Manual page for wctrans — yes it's the one from that whole POSIX Programmer's Manual situation. sit down, grab a strawberry, we're doing character mapping today 🍓✨

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🌸 PROLOG 🌸

ngl this is part of the POSIX Programmer's Manual, and there's some lore you need:

• the Linux implementation of this interface may differ — like, actually differ — so go read the corresponding Linux manual page for the deets on Linux behavior
• or honestly the interface may not even be implemented on Linux 💀

so like, vibe check your system first, iykyk.

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✨ NAME ✨

wctrans, wctrans_l — define character mapping 🦋

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💅 SYNOPSIS 💅

#include <wctype.h>

wctrans_t wctrans(const char *charclass);
wctrans_t wctrans_l(const char *charclass, locale_t locale);

periodt, that's the whole vibe.

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👑 DESCRIPTION 👑

okay so for wctrans() specifically: the functionality described on this reference page is aligned with the ISO C standard. and if there's any conflict between the requirements described here and the ISO C standard, that conflict is unintentional — no drama intended fr fr. this volume of POSIX.1‐2017 defers to the ISO C standard. she's humble like that 💜

so wctrans() and wctrans_l() are defined for valid character mapping names that get identified in the current locale. the charclass is a string that identifies a generic character mapping name — and for that name, codeset-specific information is required. the following character mapping names are defined in all locales:

• tolower
• toupper

these functions shall return a value of type wctrans_t, which can be used as the second argument to subsequent calls of towctrans() and towctrans_l(). so like, it's the little ticket you hand over later 🎀

and here's how the values get determined: wctrans() and wctrans_l() shall determine values of wctrans_t according to the rules of the coded character set defined by character mapping information in the current locale, or in the locale represented by locale, respectively — and that's the LC_CTYPE category, always.

⚠️ validity tea coming in hot: the values returned by wctrans() shall be valid until a call to setlocale() that modifies the category LC_CTYPE. so the moment someone goes and changes LC_CTYPE, your old value is giving expired-milk energy. 🙈

and the values returned by wctrans_l() shall be valid only in calls to towctrans_l() with a locale represented by locale with the same LC_CTYPE category value. no mixing and matching bestie.

💀 and the behavior is undefined if the locale argument to wctrans_l() is the special locale object LC_GLOBAL_LOCALE, or if it's not a valid locale object handle. undefined behavior is not cute. do not do this.

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🌈 RETURN VALUE 🌈

okay so:

• wctrans() and wctrans_l() shall return 0 and may set errno to indicate the error if the given character mapping name is not valid for the current locale (category LC_CTYPE)
• otherwise, they shall return a non-zero object of type wctrans_t that can be used in calls to towctrans() and towctrans_l() 🔥

zero = no ma'am. non-zero = we're so back.

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🎀 ERRORS 🎀

these functions may fail if:

• EINVAL — the character mapping name pointed to by charclass is not valid in the current locale.

and that's the only one, she's lowkey minimal.

The following sections are informative. — so like, cute but not binding, yk?

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🧚 EXAMPLES 🧚

None.

okay she said nothing, she's mysterious 💅

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🦋 APPLICATION USAGE 🦋

None.

also nothing. the silence is iconic honestly.

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⭐ RATIONALE ⭐

None.

no thoughts, head empty, still correct. periodt.

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🌸 FUTURE DIRECTIONS 🌸

None.

the future is a blank canvas and we love that for her ✨

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💖 SEE ALSO 💖

• towctrans()
• The Base Definitions volume of POSIX.1‐2017, <wctype.h>

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👑 COPYRIGHT 👑

okay legal bestie moment, we gotta do this part properly so here it is, all of it:

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 little manual page was brought to you by IEEE/The Open Group, dated 2017, and it answers to the name WCTRANS(3POSIX) 👑 see you in the next one, mwah 💜