FPUTC(P) POSIX Programmer's Manual FPUTC(P)
fputc - put a byte on a stream
int fputc(int c, FILE *stream);
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 st_ctime and st_mtime fields of the file shall be marked for update between the suc-
cessful 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().
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.
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
process would be delayed in the write operation.
EBADF The file descriptor underlying stream is not a valid file descriptor open for writ-
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 process' file size limit.
EFBIG The file is a regular file and an attempt was made to write at or beyond the offset
EINTR The write operation was terminated due to the receipt of a signal, and no data was
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
process is neither ignoring nor blocking SIGTTOU, and the process group of the
process is orphaned. This error may also be returned under implementation-defined
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 capabil-
ities of the device.
The following sections are informative.
ferror() , fopen() , getrlimit() , putc() , puts() , setbuf() , ulimit() , the Base Defi-
nitions volume of IEEE Std 1003.1-2001, <stdio.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 FPUTC(P)