PUTC(3S)                             SysV                             PUTC(3S)



NAME
     putc, putchar, fputc, putw - put character or word on a stream

SYNOPSIS
     #include <stdio.h>

     int putc (c, stream)
     int c;
     FILE *stream;

     int putchar (c)
     int c;

     int fputc (c, stream)
     int c;
     FILE *stream;

     int putw (w, stream)
     int w;
     FILE *stream;

DESCRIPTION
     The putc macro writes the character c to the output specified by the
     stream argument.  The character is written at the position at which the
     file pointer is currently pointing, if defined.

     The agruments are defined as follows:

     stream
          Points to the file structure of an open file.

     c    Specifies the character to be written.

     The putchar macro is the same as the putc() macro except that putchar
     writes to the standard output.

     The fputc function works the same as the putc() macro, but fputc is a
     true function rather than a macro. It runs more slowly than putc, but
     takes less space per invocation.

     Because  putc is implemented as a macro, it incorrectly treats a stream
     argument with side effects, such as putc(c, *f++). For such cases, use
     the fputc function. Also, use fputc when you need to pass a pointer to
     this function as a argument to another function.

     The putw function writes the word (int) specified by the w argument to
     the output specified by the stream argument. The word is written at the
     position at which the file pointer, if defined, is pointing. The size of
     a word is the size of an integer and varies from machine to machine. The
     putw function does not assume or cause special alignment of the data in
     the file.

     Because of possible differences in word length and byte ordering, files
     written using the putw function are machine-dependent, and may not be
     readable using the getw function on a different processor.  The st_ctime
     and st_mtime fields of the file are marked for update between the
     successful execution of the putc, putw, putchar, or fputc function, and
     the next successful completion of a call to the fflush or fclose function
     on the same stream, or a call to the exit (2) or abort(3C) function.

DIAGNOSTICS

     Upon successful completion, these functions each return the value
     written. If these functions fail, they return the constant EOF. They fail
     if the stream argument is not open for writing, or if the output file
     size cannot be increased. Because the EOF value is a valid integer, you
     should use the ferror function to detect the putw argument errors.

ERRORS
     The putc, putw, putchar, and fputc functions fail if either the stream is
     unbuffered, or the stream's buffer needed to be flushed and the function
     call caused an underlying write or lseek to be invoked. In addition, the
     putc, putw, putchar, or fputc fail if

     [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 writing.

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

     [EINTR]        The read operation was interrupted by a signal which was
                    caught, and no data was transferred.

     [EIO]          The implementation supports job control, 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.

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

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

SEE ALSO
     getc(3S), getwc(3S), printf(3S), puts(3S), putwc(3S),