MBSTOWCS(3POSIX)

💖 MBSTOWCS(3POSIX) 💖

okay bestie, so this is a page from the POSIX Programmer's Manual — that's the manual, girl, and this particular page is MBSTOWCS(3POSIX). Pull up a chair, we're converting strings to wide strings and it's giving iconic. ✨

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🌸 PROLOG 🌸

So real talk: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ — so like, consult the corresponding Linux manual page for the deets on Linux behavior, mkay? Or honestly? The interface might not even be implemented on Linux at all. 💀 Not every system shows up to the party.

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👑 NAME 👑

mbstowcs — convert a character string to a wide-character string

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🎀 SYNOPSIS 🎀

#include <stdlib.h>

size_t mbstowcs(wchar_t *restrict pwcs, const char *restrict s,
    size_t n);

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✨ DESCRIPTION ✨

The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional — nobody's trying to start drama. This volume of POSIX.1‐2017 defers to the ISO C standard. periodt.

The mbstowcs() function shall convert a sequence of characters that begins in the initial shift state from the array pointed to by s into a sequence of corresponding wide-character codes, and shall store not more than n wide-character codes into the array pointed to by pwcs.

No characters that follow a null byte shall be examined or converted — and heads up, that null byte gets converted into a wide-character code with value 0. Each character shall be converted as if by a call to mbtowc(), except that the shift state of mbtowc() is not affected. bestie the shift state is untouched, she said what she said. 💅

No more than n elements shall be modified in the array pointed to by pwcs.

⚠️ If copying takes place between objects that overlap, the behavior is undefined. like, do not. do not do that. 🫠

The behavior of this function shall be affected by the LC_CTYPE category of the current locale.

And here's the cute little trick: if pwcs is a null pointer, mbstowcs() shall return the length required to convert the entire array regardless of the value of n — but no values are stored. it's giving window shopping, no money spent. 🛍️

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🦋 RETURN VALUE 🦋

If an invalid character is encountered, mbstowcs() shall return (size_t)-1 and shall set errno to indicate the error. 😭

Otherwise, mbstowcs() shall return the number of the array elements modified (or required if pwcs is null), not including a terminating 0 code, if any.

🚨 And the array shall not be zero-terminated if the value returned is n. keep that in your notes bestie, that's a real one.

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🌈 ERRORS 🌈

The mbstowcs() function shall fail if:

• EILSEQ — An invalid character sequence is detected. In the POSIX locale an [EILSEQ] error cannot occur since all byte values are valid characters. iconic behavior honestly, POSIX locale said "everyone's valid here" 💜

The following sections are informative.

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💀 EXAMPLES 💀

None.

(she said nothing, and that's fine, that's her journey)

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🧚 APPLICATION USAGE 🧚

None.

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🌸 RATIONALE 🌸

None.

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⭐ FUTURE DIRECTIONS ⭐

None.

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🍓 SEE ALSO 🍓

• mblen()
• mbtowc()
• wctomb()
• wcstombs()

The Base Definitions volume of POSIX.1‐2017, <stdlib.h>

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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, no cap. this one was brought to you by IEEE/The Open Group, 2017 — 2017 was a year, and this page came out of it. mwah. 💖✨🫶