73 lines
1.6 KiB
Text
73 lines
1.6 KiB
Text
|
.TH FVERSION 2
|
||
|
|
.SH NAME
|
||
|
|
fversion \- initialize 9P connection and negotiate version
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.nf
|
||
|
|
.PP
|
||
|
|
.ft L
|
||
|
|
#include <u.h>
|
||
|
|
#include <libc.h>
|
||
|
|
.PP
|
||
|
|
.ft P
|
||
|
|
.B
|
||
|
|
int fversion(int fd, int bufsize, char *version, int nversion)
|
||
|
|
.SH DESCRIPTION
|
||
|
|
.PP
|
||
|
|
.I Fversion
|
||
|
|
is used to initialize the 9P connection represented by
|
||
|
|
.I fd
|
||
|
|
and to negotiate the version of the protocol to be used.
|
||
|
|
.PP
|
||
|
|
The
|
||
|
|
.I bufsize
|
||
|
|
determines the size of the I/O buffer used to stage 9P requests to the server,
|
||
|
|
subject to the constraints of the server itself.
|
||
|
|
The
|
||
|
|
.I version
|
||
|
|
is a text string that represents the highest version level the protocol will support.
|
||
|
|
The
|
||
|
|
.I version
|
||
|
|
will be overwritten with the negotiated, possibly lower, version of the protocol.
|
||
|
|
The return value of
|
||
|
|
.I fversion
|
||
|
|
is the length of the returned version string; the value of
|
||
|
|
.I nversion
|
||
|
|
is therefore not the length of the version string presented to the system call,
|
||
|
|
but the total length of the buffer to accept the final result, in the manner of a read system call.
|
||
|
|
.PP
|
||
|
|
Default values of zero for
|
||
|
|
.I bufsize
|
||
|
|
and the empty string for
|
||
|
|
.I version
|
||
|
|
will negotiate sensible defaults for the connection.
|
||
|
|
If
|
||
|
|
.I version
|
||
|
|
is the empty string,
|
||
|
|
.I nversion
|
||
|
|
must still be large enough to receive the returned version string.
|
||
|
|
.PP
|
||
|
|
The interpretation of the version strings is defined in
|
||
|
|
.IR version (5).
|
||
|
|
.PP
|
||
|
|
It is rare to use
|
||
|
|
.IR fversion
|
||
|
|
directly; usually the default negotiation performed
|
||
|
|
by the kernel during
|
||
|
|
.B mount
|
||
|
|
(see
|
||
|
|
.IR bind (2))
|
||
|
|
or even more commonly
|
||
|
|
.B amount
|
||
|
|
(see
|
||
|
|
.IR auth (2))
|
||
|
|
is sufficient.
|
||
|
|
.SH SOURCE
|
||
|
|
.B /sys/src/libc/9syscall
|
||
|
|
.SH SEE ALSO
|
||
|
|
.IR intro (5),
|
||
|
|
.IR version (5),
|
||
|
|
.IR fauth (2).
|
||
|
|
.SH DIAGNOSTICS
|
||
|
|
Sets
|
||
|
|
.IR errstr .
|