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

       None.

       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                                        FPUTWC(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 fputwc() function shall write the character corresponding to the wide-character code wc to the output
       stream  pointed to by stream, at the position indicated by the associated file-position indicator for the
       stream (if defined), and advances the indicator appropriately. If the  file  cannot  support  positioning
       requests,  or  if the stream was opened with append mode, the character is appended to the output stream.
       If an error occurs while writing the character, the shift  state  of  the  output  file  is  left  in  an
       undefined state.

       The  last data modification and last file status change timestamps of the file shall be marked for update
       between the successful execution of fputwc() and the next successful completion of a call to fflush()  or
       fclose() on the same stream or a call to exit() or abort().

       The fputwc() function shall not change the setting of errno if successful.

       The fputwc() function shall fail if either the stream is unbuffered or data in the stream's buffer  needs
       to be written, and:

       EAGAIN The  O_NONBLOCK  flag  is  set  for  the file descriptor underlying stream and the thread would be
              delayed in the write operation.

       EBADF  The file descriptor underlying stream is not a valid file descriptor open for writing.

       EFBIG  An attempt was made to write to a file that exceeds the maximum file size or the file  size  limit
              of the process.

       EFBIG  The  file  is  a  regular  file  and  an attempt was made to write at or beyond the offset maximum
              associated with the corresponding stream.

       EILSEQ The wide-character code wc does not correspond to a valid character.

       EINTR  The write 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  a  member  of  a  background  process  group
              attempting to write to its controlling terminal, TOSTOP is set, the calling thread is not blocking
              SIGTTOU,  the  process  is not ignoring SIGTTOU, and the process group of the process is orphaned.
              This error may also be returned under implementation-defined conditions.

       ENOSPC There was no free space remaining on the device containing the file.

       EPIPE  An attempt is made to write to a pipe or FIFO that is not open  for  reading  by  any  process.  A
              SIGPIPE signal shall also be sent to the thread.

       The fputwc() 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.

       fputwc — put a wide-character code on 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,  fputwc()  shall  return  wc.   Otherwise,  it shall return WEOF, the error
       indicator for the stream shall be set, and errno shall be set to indicate the error.

Section2.5, StandardI/OStreams, ferror(), fopen(), setbuf(), ulimit()

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

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

       wint_t fputwc(wchar_t wc, FILE *stream);