VFWPRINTF(3P)

✨ vfwprintf, vswprintf, vwprintf — POSIX Programmer's Manual (3P) ✨

okay bestie, welcome to the POSIX Programmer's Manual 💖 this one's the manual page for vfwprintf, vswprintf, and vwprintf, and it's literally the wide-character formatted-output girlies that take a stdarg argument list. let's get into it 🫶

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🚨 PROLOG 🚨

so like, real talk first:

• this manual page is part of the POSIX Programmer's Manual.
• the Linux implementation of this interface may differ — pls go consult the corresponding Linux manual page for the deets on Linux behavior 🙈
• or, plot twist, the interface may not be implemented on Linux at all. yeah. it's giving "check your platform first" 💀

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👑 NAME 👑

vfwprintf, vswprintf, vwprintf — wide-character formatted output of a stdarg argument list ✨

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🌸 SYNOPSIS 🌸

#include <stdarg.h>
#include <stdio.h>
#include <wchar.h>

int vfwprintf(FILE *restrict stream, const wchar_t *restrict format,
    va_list arg);
int vswprintf(wchar_t *restrict ws, size_t n,
    const wchar_t *restrict format, va_list arg);
int vwprintf(const wchar_t *restrict format, va_list arg);

the restrict keywords are doing their main character thing, we respect them 💅

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🦋 DESCRIPTION 🦋

so the functionality described on this reference page is aligned with the ISO C standard. if there's any conflict between what's written here and the ISO C standard, that conflict is unintentional — no beef, no drama, it's just an oopsie. this volume of POSIX.1‐2017 defers to the ISO C standard, periodt. 👑

now the actual tea:

vfwprintf(), vswprintf(), and vwprintf() shall be equivalent to fwprintf(), swprintf(), and wprintf() respectively — literally the same energy — except that instead of being called with a variable number of arguments, they get called with an argument list as defined by <stdarg.h>. that's the whole plot twist. that's it. that's the difference. 🎀

and here's the important bit, so listen up:

these functions shall not invoke the va_end macro. BUT — and this is the part where you go 😭 — because these functions do invoke the va_arg macro, the value of ap after the return is unspecified. not undefined, unspecified. still not something you wanna build your whole personality around tho. ngl.

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🔥 RETURN VALUE 🔥

refer to fwprintf(). yeah that's it, they're pointing you at the other page. iykyk. 💅

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💀 ERRORS 💀

refer to fwprintf(). same vibe, same referral. go read that one bestie.

the following sections are informative. (translation: cute bonus content, not the law 📖✨)

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🌈 EXAMPLES 🌈

none. 😭 literally nothing. no examples. an empty plate. we move.

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🧚 APPLICATION USAGE 🧚

if you're using these functions, your app should call va_end(ap) afterwards to clean up. like, clean up after yourself, bestie. don't leave ap just sitting there. 🫶

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💜 RATIONALE 💜

none. no reasoning given. we simply do not explain ourselves. 💅

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⭐ FUTURE DIRECTIONS ⭐

none. the future is bright and also empty. ✨

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🎀 SEE ALSO 🎀

• Section 2.5, Standard I/O Streams, fwprintf()
• The Base Definitions volume of POSIX.1‐2017, <stdarg.h>, <stdio.h>, <wchar.h>

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📜 COPYRIGHT 📜

okay this part is the serious part, so like, actual attention pls:

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 lil masterpiece is brought to you by IEEE and The Open Group, dated 2017, and it lives under the name VFWPRINTF(3P). go forth and format your wide characters, you absolute icon. no cap. periodt. 💅✨