FGETWC(3P)

💖 FGETWC(3P) 💖

okay bestie so this one is from the POSIX Programmer's Manual, and before we even get into it, real talk:

⚠️ heads up! The Linux implementation of this interface may differ (so like, go check the corresponding Linux manual page for the deets on Linux behavior), or honestly the interface may just... not be implemented on Linux at all. 🙈

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✨ PROLOG ✨

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.

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🌸 NAME 🌸

fgetwc — get a wide-character code from a stream

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🦋 SYNOPSIS 🦋

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

wint_t fgetwc(FILE *stream);

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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 the requirements described here and the ISO C standard, that's unintentional, okay? This volume of POSIX.1‐2017 defers to the ISO C standard. periodt.

The fgetwc() function shall obtain the next character (if present) from the input stream pointed to by stream, convert that to the corresponding wide-character code, and advance the associated file position indicator for the stream (if defined).

If an error occurs, the resulting value of the file position indicator for the stream is unspecified. 😭 not the unspecified behavior.

The fgetwc() function may mark the last data access timestamp of the file associated with stream for update. The last data access timestamp shall be marked for update by the first successful execution of fgetwc(), fgetws(), fwscanf(), getwc(), getwchar(), vfwscanf(), vwscanf(), or wscanf() using stream that returns data not supplied by a prior call to ungetwc().

The fgetwc() function shall not change the setting of errno if successful. ✨ (she's polite like that)

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🎀 RETURN VALUE 🎀

Upon successful completion, the fgetwc() function shall return the wide-character code of the character read from the input stream pointed to by stream converted to a type wint_t. 💖

If the end-of-file indicator for the stream is set, or if the stream is at end-of-file, the end-of-file indicator for the stream shall be set and fgetwc() shall return WEOF.

If a read error occurs, the error indicator for the stream shall be set, fgetwc() shall return WEOF, and shall set errno to indicate the error.

If an encoding error occurs, the error indicator for the stream shall be set, fgetwc() shall return WEOF, and shall set errno to indicate the error.

so basically WEOF is giving "something went wrong OR we're done here" and you literally cannot tell which without extra steps. iconic behavior, honestly. 💀

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🔥 ERRORS 🔥

The fgetwc() function shall fail if data needs to be read and:

• EAGAIN — The O_NONBLOCK flag is set for the file descriptor underlying stream and the thread would be delayed in the fgetwc() operation.
• EBADF — The file descriptor underlying stream is not a valid file descriptor open for reading.
• EILSEQ — The data obtained from the input stream does not form a valid character.
• EINTR — The read operation was terminated due to the receipt of a signal, and no data was transferred.
• EIO — A physical I/O error has occurred, or the process is in a background process group attempting to read from its controlling terminal, and either the calling thread is blocking SIGTTIN or the process is ignoring SIGTTIN or the process group of the process is orphaned. This error may also be generated for implementation-defined reasons.
• EOVERFLOW — The file is a regular file and an attempt was made to read at or beyond the offset maximum associated with the corresponding stream.

The fgetwc() function may fail if:

• ENOMEM — Insufficient storage space is available.
• ENXIO — A request was made of a nonexistent device, or the request was outside the capabilities of the device.

The following sections are informative.

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⭐ EXAMPLES ⭐

None. 💀 (yes bestie, literally none. we move.)

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🌈 APPLICATION USAGE 🌈

The ferror() or feof() functions must be used to distinguish between an error condition and an end-of-file condition. fr fr, this is not optional — WEOF alone will not tell you which one it is.

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🦋 RATIONALE 🦋

None.

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💜 FUTURE DIRECTIONS 💜

None.

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👑 SEE ALSO 👑

• Section 2.5, Standard I/O Streams, feof(), ferror(), fopen()
• The Base Definitions volume of POSIX.1‐2017, <stdio.h>, <wchar.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 thing bestie!! 🫶 this absolute baddie of a page came to you from IEEE/The Open Group, dated 2017, living under the name FGETWC(3P). go read a wide character, slay, and don't forget your ferror()/feof() check. mwah 💅✨