vrb_resize(3) [debian man page]

vrb_resize(3)						      VRB Programmer's Manual						     vrb_resize(3)

NAME

       vrb_resize - create a new virtual ring buffer

LIBRARY

       -lvrb

SYNOPSIS

       #include <vrb.h>

       vrb_p vrb_resize(size_t size, const char *name);

DESCRIPTION

       vrb_resize changes the size of a virtual ring buffer if the data in the source buffer will fit in the requested space.

ARGUMENTS

       vrb_p vrb
       specifies the ring buffer which will be resized.

       size_t size
       specifies  the requested minimum buffer size to be allocated.  The given value will be rounded up to the nearest or equal whole multiple of
       the system page size.  The virtual ring buffer is implemented by mapping two adjacent blocks of memory to the same  memory  object.   Thus,
       twice  as  much virtual address space will be used and the specified size must be less than half of the available virtual address space for
       this process.

       const char *name
       specifies an optional name of a file to be used as backing store via mmap(2) in a mounted filesystem in which the process has write permis-
       sion.   If  the named file cannot be opened for write, an error will occur.  If NULL is given, swap space will be used as backing store via
       shmat(2).

RETURN VALUE

       int
       On success, 0 is returned.  Otherwise, -1 is returned.

ERRORS

       If an error is returned, then errno will have one of the following values:

       ENOSPC The data in the current virtual ring buffer will not fit into the requested space.

       EINVAL A buffer size was requested which is too large for address space allocation arithmetic.

       ENOMEM Out of memory allocating the virtual ring buffer structure.

       -      An errno value set by a failing system call.

SEE ALSO

       vrb(3),	vrb_capacity(3),  vrb_data_len(3),  vrb_data_ptr(3),  vrb_destroy(3),  vrb_get(3),   vrb_get_min(3),   vrb_give(3),   vrb_init(3),
       vrb_init_opt(3),   vrb_is_empty(3),  vrb_is_full(3),  vrb_is_not_empty(3),  vrb_is_not_full(3),	vrb_move(3),  vrb_new(3),  vrb_new_opt(3),
       vrb_put(3), vrb_put_all(3), vrb_read(3), vrb_read_min(3), vrb_space_len(3),  vrb_space_ptr(3),  vrb_take(3),  vrb_uninit(3),  vrb_write(3),
       vrb_write_min(3)

vrb								    2002-09-30							     vrb_resize(3)

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)