lis_unregister_strdev.9

7号信令功能代码,为开源代码

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accumulate
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abbreviate A
join-authors ", " ", " " and "
et-al " et al" 2 3
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.\"
.\"
.TH LIS_UNREGSITER_STRDEV 9 "2004/01/12 23:33:08" "LiS-2_16_18-8" "Linux STREAMS DDI/DKI"
.SH NAME
.B lis_unregister_strdev
\- unregister a \fISTREAMS\fR device
.SH SYNOPSIS
.PP
.B #include <sys/stream.h>
.HP 8
.BI "int " retval " = lis_unregister_strdev(major_t " major );
.SH DESCRIPTION
.PP
.BR lis_unregister_strdev ()
deregisters a
.IR STREAMS (4)
driver previously registered with
.BR lis_register_strdev (9).
.PP
.BR lis_unregister_strdev ()
removes the
.IR STREAMS (4)
driver identified by its major device number,
.IR major ,
from the
.IR STREAMS (4)
device switch table and deregisters the character major
number,
.IR major ,
from the
.B Linux
kernel using
.BR unregister_chrdev ().
Before removing the
.IR STREAMS (4)
driver,
.B LiS
.[
LiS
.]
will also clear any autopush list associated with the
.IR STREAMS (4)
driver.
.SH "RETURN VALUES"
.PP
Upon succes,
.BR lis_unregister_strdev ()
returns zero (0).
Upon failure,
.BR lis_unregister_strdev ()
returns a negative error number.
.SH ERRORS
.PP
When
.BR lis_unregister_strdev ()
fails, it returns the negative of one of the following errors:
.PP
.TP 12
.RB [ ENODEV ]
The character device major number
.IR major ,
is not registered to
.B LiS\c
.
.[
LiS
.]
.TP 12
.RB [ EBUSY ]
The
.IR STREAMS (4)
driver identified by
.I major
has open file descriptors.
.SH CAVEATS
.PP
Although
.B LiS
.[
LiS
.]
will demand load a
.B Linux
kernel module supporting a
.IR STREAMS (4)
driver, it will not remove that module once
it is deregistered.
.B Linux
does, however, provide a mechanism for autocleaning kernel modules that have a
zero reference count and this facility could be used instead.
.SH EXAMPLES
.PP
Following is an example that demonstrates how 4 major device numbers could be
registered and deregistered against a
.IR STREAMS (4)
driver:
.sp
.in +4
.nf
\fC\s-2\
#define X_MAJOR 222
#define X_NMAJOR 4
#define X_NMINOR 255
#define X_DRV_NAME "example"

int x_initialized = 0;
ushort x_majors[X_NMAJOR] = { X_CMAJOR, };

void x_init(void)
{
    int err, mindex;
    for (mindex = 0; mindex < X_NMAJOR; mindex++) {
	if ((err = lis_register_strdev(x_majors[mindex], &x_info,
		                       X_NMINOR, X_DRV_NAME)) < 0) {
	    if (!mindex) {
		cmn_err(CE_PANIC,
			"%s: could not register 1'st major %d",
			X_DRV_NAME, x_majors[mindex]);
		x_initialized = err;
		return;
	    }
	    cmn_err(CE_WARN, "%s: could not register %d'th major",
		    X_DRV_NAME, mindex + 1);
	    x_majors[mindex] = 0;
	} else if (mindex)
	    x_majors[mindex] = err;
    }
    x_initialized = 1;
    return;
}

void x_terminate(void)
{
    int err, mindex;
    for (mindex = 0; mindex < X_NMAJOR; mindex++) {
	if (x_majors[mindex]) {
	    if ((err = lis_unregister_strdev(x_majors[mindex])))
		cmn_err(CE_PANIC, "%s: could not unregister major %d",
			X_DRV_NAME, x_majors[mindex]);
	    if (mindex)
		x_majors[mindex] = 0;
	}
    }
    return;
}
\s+2\fR
.fi
.SH "SEE ALSO"
.PP
.BR lis_register_strdev (9),
.BR lis_register_strmod (9),
.BR lis_unregister_strdev (9).
.SH VERSIONS
.PP
This manpage was written for
.B LiS\c
.
.[
LiS
.]
.PP
.BR lis_unregister_strdev ()
is an LiS-specific function that first appeared in early version of
.BR LiS .
.\"
.\"
.XX
.[
magic
.]
.[
svr42
.]
.[
svr4
.]
.\"
.\"
.[
$LIST$
.]
.TA