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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.
NAME
fgetwc — get a wide-character code from a stream
SYNOPSIS
#include <stdio.h>
#include <wchar.h>
wint_t fgetwc(FILE *stream);
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. This volume of
POSIX.1‐2008 defers to the ISO C standard.
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.
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.
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.
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.
EXAMPLES
None.
APPLICATION USAGE
The ferror() or feof() functions must be used to distinguish between an error condition and an end-of-
file condition.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
Section 2.5, Standard I/O Streams, feof(), ferror(), fopen()
The Base Definitions volume of POSIX.1‐2008, <stdio.h>, <wchar.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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 .
IEEE/The Open Group 2013 FGETWC(3POSIX)