putc(3S)                                                 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 onto the output stream
          at the position where the file pointer, if defined, is
          pointing.  The putchar macro is defined as putc(c, stdout).

          fputc behaves like putc, but is a function rather than a
          macro.  fputc runs more slowly than putc, but it takes less
          space per invocation and its name can be passed as an argu-
          ment to a function.

          putw writes the word (32-bit integer on the Macintosh II) w
          to the output stream at the position at which the file
          pointer, if defined, is pointing.  putw neither assumes nor
          causes special alignment in the file.

          Output streams, with the exception of the standard error
          stream stderr, are by default buffered if the output refers
          to a file and line-buffered if the output refers to a termi-
          nal.  The standard error output stream stderr is by default
          unbuffered, but use of freopen (see fopen(3S)) causes it to
          become buffered or line-buffered.  When an output stream is
          unbuffered information, it is queued for writing on the des-
          tination file or terminal as soon as written; when it is
          buffered, many characters are saved up and written as a
          block; when it is line-buffered, each line of output is
          queued for writing on the destination terminal as soon as
          the line is completed (i.e., as soon as a newline character
          is written or terminal input is requested).  setbuf(3S) may
          be used to change the stream's buffering strategy.




     April, 1990                                                     1

     putc(3S)                                                 putc(3S)



     RETURN VALUE
          On success, these functions each return the value they have
          written.  On failure, they return the constant EOF.  This
          occurs if the file stream is not open for writing or if the
          output file cannot be grown.  Because EOF is a valid in-
          teger, ferror(3S) should be used to detect putw errors.

     SEE ALSO
          fclose(3S), ferror(3S), fopen(3S), fread(3S), getc(3S),
          printf(3S), puts(3S), setbuf(3S).

     BUGS
          Because it is implemented as a macro, putc treats incorrect-
          ly a stream argument with side effects.  In particular,
          putc(c, *f++); doesn't work sensibly.  fputc should be used
          instead.
          Because of possible differences in word length and byte ord-
          ering, files written using putw are machine-dependent and
          may not be read using getw on a different processor.




































     2                                                     April, 1990