12872 ioctl(2) needs additional ENOTTY documentation

Reviewed by: Ryan Zezeski <ryan@zinascii.com>
Reviewed by: Andy Fiddaman <omnios@citrus-it.co.uk>
Approved by: Dan McDonald <danmcd@joyent.com>

1 files changed, 9 insertions, 15 deletions

diff --git a/usr/src/man/man2/ioctl.2 b/usr/src/man/man2/ioctl.2
index 73e5084d27..59271fdcce 100644
--- a/usr/src/man/man2/ioctl.2
+++ b/usr/src/man/man2/ioctl.2
@@ -44,11 +44,10 @@
 .\" Portions Copyright (c) 1992, X/Open Company Limited  All Rights Reserved
 .\" Copyright (c) 1996, Sun Microsystems, Inc.  All Rights Reserved.
 .\"
-.TH IOCTL 2 "Feb 15, 1996"
+.TH IOCTL 2 "June 18, 2020"
 .SH NAME
 ioctl \- control device
 .SH SYNOPSIS
-.LP
 .nf
 #include <unistd.h>
 #include <stropts.h>
@@ -57,12 +56,10 @@ ioctl \- control device
 .fi
 
 .SH DESCRIPTION
-.sp
-.LP
 The \fBioctl()\fR function performs a variety of control functions on devices
 and streams. For non-streams files, the functions performed by this call are
 device-specific control functions.  The \fIrequest\fR argument and an optional
-third argument with varying type are passed to the file designated by
+third argument with varying type are passed to the device file designated by
 \fIfildes\fR and are interpreted by the device driver.
 .sp
 .LP
@@ -81,16 +78,12 @@ to a device-specific data structure.
 .LP
 In addition to device-specific and streams functions, generic functions are
 provided by more than one device driver (for example, the general terminal
-interface.)  See \fBtermio\fR(7I)).
+interface or disk interfaces.)  See \fBtermio\fR(7I)), \fBdkio\fR(7I), etc..
 .SH RETURN VALUES
-.sp
-.LP
 Upon successful completion, the value returned depends upon the device control
 function, but must be a non-negative integer.  Otherwise, \fB\(mi1\fR is
 returned and \fBerrno\fR is set to indicate the error.
 .SH ERRORS
-.sp
-.LP
 The \fBioctl()\fR function will fail for any type of file if:
 .sp
 .ne 2
@@ -144,6 +137,7 @@ to by \fIarg\fR, but \fIarg\fR points to an illegal address.
 .ad
 .RS 11n
 The \fIrequest\fR or \fIarg\fR argument is not valid for this device.
+Many devices return \fBENOTTY\fR for an unknown \fIrequest\fR.
 .RE
 
 .sp
@@ -171,8 +165,10 @@ is no longer active.
 \fB\fBENOTTY\fR\fR
 .ad
 .RS 11n
-The \fIfildes\fR argument is not associated with a streams device that accepts
+The \fIfildes\fR argument is not associated with a device that accepts
 control functions.
+.sp
+The device driver does not know the \fIrequest\fR command.
 .RE
 
 .sp
@@ -183,6 +179,8 @@ control functions.
 .RS 11n
 The \fIrequest\fR and \fIarg\fR arguments are valid for this device driver, but
 the service requested can not be performed on this particular subdevice.
+.sp
+The device driver does not support the \fBioctl()\fR function.
 .RE
 
 .sp
@@ -199,8 +197,6 @@ corresponding device driver does not support the \fBioctl()\fR function.
 .LP
 Streams errors are described in \fBstreamio\fR(7I).
 .SH ATTRIBUTES
-.sp
-.LP
 See \fBattributes\fR(5) for descriptions of the following attributes:
 .sp
 
@@ -215,6 +211,4 @@ Interface Stability	Standard
 .TE
 
 .SH SEE ALSO
-.sp
-.LP
 \fBattributes\fR(5), \fBstandards\fR(5), \fBstreamio\fR(7I), \fBtermio\fR(7I)