.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
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.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" SUCH DAMAGE.
.\"
.\" Note: The date here should be updated whenever a non-trivial
.\" change is made to the manual page.
.Dd September 27, 2006
.Dt EXAMPLE 9
.Os
.Sh NAME
.Nm example
.Nd "example kernel interface manual page"
.Sh SYNOPSIS
.In sys/example.h
.Ft int
.Fn example "char *ptr" "int mode"
.Sh DESCRIPTION
This is an example manual page for the
.Fn example
kernel function.
It is intended that this example can be used as a template
when writing a new manual page.
.Pp
The
.Fn example
function takes two arguments:
.Fa ptr
and
.Fa mode .
The argument
.Fa mode
may have one of the following values:
.Bl -tag -width "EXAMPLE_ONE"
.It Dv EXAMPLE_ONE
First example of a defined variable.
.Dv EXAMPLE_ONE
is described below.
.It Dv EXAMPLE_TWO
Second example.
.El
.Pp
The above values are defined in
.In example.h
as follows:
.Bd -literal
#define EXAMPLE_ONE  1
#define EXAMPLE_TWO  2
.Ed
.Sh IMPLEMENTATION NOTES
The
.Fn example
function is not actually implemented.
.Sh LOCKING
The
.Va example_lock
lock must be held before
.Fn example
is called.
.Pp
Since
.Va example_lock
is a
.Xr mutex 9 ,
no sleepable locks (i.e.,
.Xr sx 9
locks) can be acquired in
.Fn example .
.Sh RETURN VALUES
The
.Fn example
function returns the value 0 if successful;
otherwise one of the values listed in the
.Sx ERRORS
section is returned, to indicate the error.
.Sh EXAMPLES
.Bd -literal
	int error;

	mtx_lock(&example_lock);
	if ((error = example(NULL, EXAMPLE_ONE)) != 0) {
		mtx_unlock(&example_lock);
		return (error);
	}
	mtx_unlock(&example_lock);
.Ed
.Sh COMPATIBILITY
The
.Fn example
function has no known compatibility issues.
.Sh ERRORS
.\" Delete any errno's that are not returned by your
.\" function or system call and then tailor the
.\" remaining text as needed.
The
.Fn example
function will fail if:
.Bl -tag -width Er
.It Bq Er EPERM
Operation not permitted.
.It Bq Er ENOENT
No such file or directory.
.It Bq Er ESRCH
No such process.
.It Bq Er EINTR
Interrupted system call.
.It Bq Er EIO
Input/output error.
.It Bq Er ENXIO
Device not configured.
.It Bq Er E2BIG
Argument list too long.
.It Bq Er ENOEXEC
Exec format error.
.It Bq Er EBADF
Bad file descriptor.
.It Bq Er ECHILD
No child processes.
.It Bq Er EDEADLK
Resource deadlock avoided.
.It Bq Er ENOMEM
Cannot allocate memory.
.It Bq Er EACCES
Permission denied.
.It Bq Er EFAULT
Bad address.
.It Bq Er ENOTBLK
Block device required.
.It Bq Er EBUSY
Device busy.
.It Bq Er EEXIST
File exists.
.It Bq Er EXDEV
Cross-device link.
.It Bq Er ENODEV
Operation not supported by device.
.It Bq Er ENOTDIR
Not a directory.
.It Bq Er EISDIR
Is a directory.
.It Bq Er EINVAL
Invalid argument.
.It Bq Er ENFILE
Too many open files in system.
.It Bq Er EMFILE
Too many open files.
.It Bq Er ENOTTY
Inappropriate ioctl for device.
.It Bq Er ETXTBSY
Text file busy.
.It Bq Er EFBIG
File too large.
.It Bq Er ENOSPC
No space left on device.
.It Bq Er ESPIPE
Illegal seek.
.It Bq Er EROFS
Read-only file system.
.It Bq Er EMLINK
Too many links.
.It Bq Er EPIPE
Broken pipe.
.It Bq Er EDOM
Numerical argument out of domain.
.It Bq Er ERANGE
Result too large.
.It Bq Er EAGAIN
Resource temporarily unavailable.
.It Bq Er EWOULDBLOCK
Operation would block.
.It Bq Er EINPROGRESS
Operation now in progress.
.It Bq Er EALREADY
Operation already in progress.
.It Bq Er ENOTSOCK
Socket operation on non-socket.
.It Bq Er EDESTADDRREQ
Destination address required.
.It Bq Er EMSGSIZE
Message too long.
.It Bq Er EPROTOTYPE
Protocol wrong type for socket.
.It Bq Er ENOPROTOOPT
Protocol not available.
.It Bq Er EPROTONOSUPPORT
Protocol not supported.
.It Bq Er ESOCKTNOSUPPORT
Socket type not supported.
.It Bq Er EOPNOTSUPP
Operation not supported.
.It Bq Er EPFNOSUPPORT
Protocol family not supported.
.It Bq Er EAFNOSUPPORT
Address family not supported by protocol family.
.It Bq Er EADDRINUSE
Address already in use.
.It Bq Er EADDRNOTAVAIL
Cannot assign requested address.
.It Bq Er ENETDOWN
Network is down.
.It Bq Er ENETUNREACH
Network is unreachable.
.It Bq Er ENETRESET
Network dropped connection on reset.
.It Bq Er ECONNABORTED
Software causes connection abort.
.It Bq Er ENOBUFS
No buffer space available.
.It Bq Er EISCONN
Socket is already connected.
.It Bq Er ENOTCONN
Socket is not connected.
.It Bq Er ESHUTDOWN
Cannot send after socket shutdown.
.It Bq Er ETOOMANYREFS
Too many references: cannot splice.
.It Bq Er ETIMEDOUT
Operation timed out.
.It Bq Er ECONNREFUSED
Connection refused.
.It Bq Er ELOOP
Too many levels of symbolic links.
.It Bq Er ENAMETOOLONG
File name too long.
.It Bq Er EHOSTDOWN
Host is down.
.It Bq Er EHOSTUNREACH
No route to host.
.It Bq Er ENOTEMPTY
Directory not empty.
.It Bq Er EPROCLIM
Too many processes.
.It Bq Er EUSERS
Too many users.
.It Bq Er EDQUOT
Disc quota exceeded.
.It Bq Er ESTALE
Stale NFS file handle.
.It Bq Er EREMOTE
Too many levels of remote in path.
.It Bq Er EBADRPC
RPC struct is bad.
.It Bq Er ERPCMISMATCH
RPC version wrong.
.It Bq Er EPROGUNAVAIL
RPC program not available.
.It Bq Er EPROGMISMATCH
Program version wrong.
.It Bq Er EPROCUNAVAIL
Bad procedure for program.
.It Bq Er ENOLCK
No locks available.
.It Bq Er ENOSYS
Function not implemented.
.It Bq Er EFTYPE
Inappropriate file type or format.
.It Bq Er EAUTH
Authentication error.
.It Bq Er ENEEDAUTH
Need authenticator.
.It Bq Er EIDRM
Identifier removed.
.It Bq Er ENOMSG
No message of desired type.
.It Bq Er EOVERFLOW
Value too large to be stored in data type.
.It Bq Er ECANCELED
Operation canceled.
.It Bq Er EILSEQ
Illegal byte sequence.
.It Bq Er ENOATTR
Attribute not found.
.It Bq Er EDOOFUS
Programming error.
.El
.Sh SEE ALSO
.Xr example 1 ,
.Xr example 3 ,
.Xr example 4 ,
.Xr mdoc 7 ,
.Xr mutex 9
.Rs
.%A "A. B. Author"
.%T "Example RFC Title"
.%O RFC0000
.Re
.Rs
.%A "A. B. Author"
.%B "Example Book Title"
.%O ISBN-0-000-00000-0
.Re
.Rs
.%A "A. B. Author"
.%D "January 1997"
.%J "Example Journal Name"
.%T "Example Article Title"
.Re
.Sh HISTORY
The
.Nm
manual page example first appeared in
.Fx 6.0 .
.Pp
Some other common
.Sx HISTORY
section examples are:
.Pp
The
.Nm
manual page example first appeared in
.Bx 4.4 .
.Pp
The
.Nm
manual page example first appeared in
.At v6 .
.Sh AUTHORS
This
manual page was written by
.An Giorgos Keramidas Aq Mt keramida@FreeBSD.org .
.Sh BUGS
The actual code for this function is vaporware.