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vbuf(1) [debian man page]

VBUF(1) 						      General Commands Manual							   VBUF(1)

NAME

       vbuf - Virtual Ring Buffer shell interface

SYNOPSIS

       vbuf [options]

DESCRIPTION

       This manual page documents briefly the vbuf command.

       vbuf  is  a  program  to glue two programs (a producer and a consumer) together, one of which not being able to fulfil the other's constant
       data rate requirements.

OPTIONS

       -h
	      Show short help message.

       --help
	      Show long help message.

       -p, --progress
	      Show progress status line.

       -q, --quiet
	      Suppress progress status line.  The default is to show the progress display.

       -s size, --size=size
	      Set buffer size in bytes.  Suffixes k, m, and g may be used.  The actual size used will be rounded up for  system  mapping  require-
	      ments.  The default is 1m, or 1048576 bytes.

       -t time, --time=seconds
	      Set time in seconds between progress display refreshes.  Fractions of a second may be used.  Default is 1.500000 seconds.

       -b, --bits
	      Set progress rate display units to bits per second.

       -B, --bytes
	      Set progress rate display units to bytes per second.  The default is bytes.

       -d, --decimal
	      Set progress rate display base to decimal.  The default is decimal.

       -x, --hexadecimal
	      Set progress rate display base to hexadecimal.

       --octal
	      Set progress rate display base to octal.

       -i file, --input=file
	      Specify an input file to be opened and used instead of using stdin.

       -o file, --output=file
	      Specify an output file to be opened and used instead of using stdout.

       -M file, --mapfile=file
	      Specify  a  file	which  will be used for backing store for the virtual ring buffer.  The allows using filesystem space in case swap
	      space is full.

       -r bytes, --read-min=bytes
	      Specify the minimum number of bytes to be requested by read.  Reading will not happen unless at least  this  much  buffer  space	is
	      available.  The default is 1.

       -R bytes, --read-max=bytes
	      Specify  the maximum number of bytes to be requested by read.  Reading will not request more even if more buffer space is available.
	      The default is the full buffer size.

       -w bytes, --write-min=bytes
	      Specify the minumum number of bytes to be written.  Writing will not be done unless at least this much data is available.  Once  end
	      of file is reached on input, a smaller amount may be written.  The default is 1.

       -W bytes, --write-max=bytes
	      Specify the maximum number of bytes to be written.  Writing will not write more each time even if more data is available in the buf-
	      fer.  The default is the full buffer size.

AUTHOR

       VRB and vbuf were written by Phil Howard <vrb@ipal.org>.

       This manual page was written by Szekelyi Szabolcs <cc@mail.3d.hu>, for the Debian project (but may be used by others).

								    2006 Sep 5								   VBUF(1)

Check Out this Related Man Page

setbuf(3S)																setbuf(3S)

NAME

       setbuf(), setvbuf(), setlinebuf() - assign buffering to a stream file

SYNOPSIS


   Obsolescent Interface
DESCRIPTION

       can  be	used after a stream has been opened but before it is read or written.  It causes the array pointed to by buf to be used instead of
       an automatically allocated buffer.  If buf is the NULL pointer input/output will be completely unbuffered.

       A constant defined in the header file, tells how big an array is needed:

       can be used after a stream has been opened but before it is read or written.  type determines how stream is to be buffered.   Legal  values
       for type (defined in are:

	      causes input/output to be fully buffered.

	      causes output to be line buffered;
			  the buffer will be flushed when a newline is written, the buffer is full, or input is requested.

	      causes input/output to be completely unbuffered.

       When  an  output stream is unbuffered, information is queued for writing on the destination file or terminal as soon as written; when it is
       buffered, many characters are saved up and written as a block.  When the output stream is line-buffered, each line of output is queued  for
       writing on the destination terminal as soon as the line is completed (that is, as soon as a new-line character is written or terminal input
       is requested).  can also be used to explicitly write the buffer.

       If buf is not the NULL pointer, the array it points to is used for buffering instead of an automatically allocated buffer (from size speci-
       fies  the  size of the buffer to be used.  The constant in is suggested as a good buffer size.  If input/output is unbuffered, buf and size
       are ignored.

       By default, output to a terminal is line buffered and all other input/output is fully buffered.

       is used to change stream from block-buffered or unbuffered to line-buffered.  can be used any time the file descriptor is active.

   Obsolescent Interface
       assigns buffering to a stream file.

DIAGNOSTICS

       If an illegal value for type or size is provided, return a non-zero value.  Otherwise, the value returned will be zero.

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

       Allocating a buffer of size or bytes does not necessarily imply that all of size or bytes are used for the buffer area.

AUTHOR

       and were developed by HP.

SEE ALSO

       flockfile(3S), fopen(3S), getc(3S), malloc(3C), putc(3S), stdio(3S), thread_safety(5), glossary(9).

STANDARDS CONFORMANCE

																	setbuf(3S)
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