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

       fputc — put a byte on a stream

SYNOPSIS

       #include <stdio.h>

       int fputc(int c, 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  fputc()  function shall write the byte specified by c (converted to an unsigned char)
       to the output stream pointed to by stream, at the position  indicated  by  the  associated
       file-position  indicator  for  the  stream  (if  defined), and shall advance the indicator
       appropriately.  If the file cannot support positioning requests,  or  if  the  stream  was
       opened with append mode, the byte shall be appended to the output stream.

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

RETURN VALUE

       Upon successful completion, fputc() shall return the value it has written.  Otherwise,  it
       shall  return EOF, the error indicator for the stream shall be set, and errno shall be set
       to indicate the error.

ERRORS

       The fputc() function shall fail if either the stream is unbuffered or the stream's  buffer
       needs to be flushed, 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.

       EFBIG  An  attempt  was  made  to  write to a file that exceeds 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.

       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 fputc() 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

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Section 2.5,  Standard  I/O  Streams,  ferror(),  fopen(),  getrlimit(),  putc(),  puts(),
       setbuf(), ulimit()

       The Base Definitions volume of POSIX.1‐2008, <stdio.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 .