This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       The ferror() or feof() functions must be used to distinguish between an error condition  and  an  end-of-
       file condition.

       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 .

IEEE/The Open Group                                   2017                                        FGETWC(3POSIX)

       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.1‐2017 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.

       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.

       Thefollowingsectionsareinformative.

       None.

       None.

       fgetwc — get a wide-character code from a stream

       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.

       None.

       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.

Section2.5, StandardI/OStreams, feof(), ferror(), fopen()

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

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

       wint_t fgetwc(FILE *stream);