[unix-history] / usr / src / old / man / vwrite.2v

.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)vwrite.2v	4.1 (Berkeley) %G%
.\"
.TH VWRITE 2V deprecated
.UC 4
.SH NAME
vwrite \- write (virtually) to file
.SH SYNOPSIS
.nf
.B vwrite(filedes, buffer, nbytes)
.B char *buffer;
.fi
.SH DESCRIPTION
.B N.B.:
This call is likely to be replaced by more general virtual memory facilities
in the near future.
.PP
The
.I vwrite
system call is used in conjunction with
.I vread
to perform efficient updating of large files.
After a call to
.I vread
and updating of the data in the buffer which was given to
.I vread,
a
.I vwrite
of the same buffer to the same
.I filedes
at the same offset in the file
will cause data which has been modified since it was
.I vread
from (or
.I vwritten
to) the file to be returned to the file.
.SH SEE ALSO
vread(2)
.SH DIAGNOSTICS
Returns \-1 on error: bad descriptor, buffer address, count or alignment
as well as on physical I/O errors.
.SH BUGS
The result of
.I vwrite
is defined only when no other
.I vread's
have occurred on
.I buffer
since the one matching the
.I vwrite.
.PP
This call is peculiar to this version of UNIX.
It will be superseded by more general
virtual memory facilities in future versions of the system.
Commit	Line	Data
f42730df KM	1	.\" Copyright (c) 1980 Regents of the University of California.
	2	.\" All rights reserved. The Berkeley software License Agreement
	3	.\" specifies the terms and conditions for redistribution.
	4	.\"
	5	.\" @(#)vwrite.2v 4.1 (Berkeley) %G%
	6	.\"
	7	.TH VWRITE 2V deprecated
	8	.UC 4
	9	.SH NAME
	10	vwrite \- write (virtually) to file
	11	.SH SYNOPSIS
	12	.nf
	13	.B vwrite(filedes, buffer, nbytes)
	14	.B char *buffer;
	15	.fi
	16	.SH DESCRIPTION
	17	.B N.B.:
	18	This call is likely to be replaced by more general virtual memory facilities
	19	in the near future.
	20	.PP
	21	The
	22	.I vwrite
	23	system call is used in conjunction with
	24	.I vread
	25	to perform efficient updating of large files.
	26	After a call to
	27	.I vread
	28	and updating of the data in the buffer which was given to
	29	.I vread,
	30	a
	31	.I vwrite
	32	of the same buffer to the same
	33	.I filedes
	34	at the same offset in the file
	35	will cause data which has been modified since it was
	36	.I vread
	37	from (or
	38	.I vwritten
	39	to) the file to be returned to the file.
	40	.SH SEE ALSO
	41	vread(2)
	42	.SH DIAGNOSTICS
	43	Returns \-1 on error: bad descriptor, buffer address, count or alignment
	44	as well as on physical I/O errors.
	45	.SH BUGS
	46	The result of
	47	.I vwrite
	48	is defined only when no other
	49	.I vread's
	50	have occurred on
	51	.I buffer
	52	since the one matching the
	53	.I vwrite.
	54	.PP
	55	This call is peculiar to this version of UNIX.
	56	It will be superseded by more general
	57	virtual memory facilities in future versions of the system.