setbuffer(3BSD)      (BSD System Compatibility)      setbuffer(3BSD)


       NAME
             setbuffer, setlinebuf - (BSD) assign buffering to a stream

       SYNOPSIS
             /usr/ucb/cc [flag . . . ] file . . .
             #include <stdio.h>
             setbuffer(FILE *stream, char *buf, int size);
             setlinebuf(FILE *stream);

       DESCRIPTION
             The three types of buffering available are unbuffered, block
             buffered, and line buffered.  When an output stream is
             unbuffered, information appears on the destination file or
             terminal as soon as written; when it is block buffered many
             characters are saved up and written as a block; when it is
             line buffered characters are saved up until a NEWLINE is
             encountered or input is read from any line buffered input
             stream.  fflush [see fclose(3S)] may be used to force the
             block out early.  Normally all files are block buffered.  A
             buffer is obtained from malloc(3C) upon the first getc or
             putc(3S) on the file.

             By default, output to a terminal is line buffered, except for
             output to the standard stream stderr which is unbuffered, and
             all other input/output is fully buffered.

             setbuffer can be used after a stream has been opened but
             before it is read or written.  It uses the character array buf
             whose size is determined by the size argument instead of an
             automatically allocated buffer.  If buf is the NULL pointer,
             input/output will be completely unbuffered.  A manifest
             constant BUFSIZ, defined in the stdio.h header file, tells how
             big an array is needed:
                   char buf[BUFSIZ];

             setlinebuf is used to change the buffering on a stream from
             block buffered or unbuffered to line buffered.  Unlike
             setbuffer, it can be used at any time that the file descriptor
             is active.

             A file can be changed from unbuffered or line buffered to
             block buffered by using freopen [see fopen(3S)].  A file can
             be changed from block buffered or line buffered to unbuffered
             by using freopen followed by setbuffer with a buffer argument
             of NULL.



                           Copyright 1994 Novell, Inc.               Page 1

      setbuffer(3BSD)      (BSD System Compatibility)      setbuffer(3BSD)


      REFERENCES
            fclose(3S), fopen(3S), fprintf(3S), fread(3S), getc(3S),
            malloc(3C), putc(3S), puts(3S), setbuf(3S)

      NOTICES
            A common source of error is allocating buffer space as an
            automatic variable in a code block, and then failing to close
            the stream in the same block.








































                          Copyright 1994 Novell, Inc.               Page 2