.lf 1 ./man/man3/explain_ioctl.3
.\"
.\" libexplain - Explain errno values returned by libc functions
.\" Copyright (C) 2008-2011 Peter Miller
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 3 of the License, or (at
.\" your option) any later version.
.\"
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
.\" General Public License for more details.
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.\" You should have received a copy of the GNU General Public License
.\" along with this program. If not, see .
.\"
.ds n) explain_ioctl
.cp 0 \" Solaris defaults to ''.cp 1'', sheesh.
.TH explain_ioctl 3
.SH NAME
explain_ioctl \- explain ioctl(2) errors
.if require_index \{
.\}
.SH SYNOPSIS
#include
.sp 0.3
const char *explain_ioctl(int fildes, int request, void *data);
.br
const char *explain_errno_ioctl(int errnum, int fildes, int request,
void *data);
.br
void explain_message_ioctl(char *message, int message_size, int fildes,
int request, void *data);
.br
void explain_message_errno_ioctl(char *message, int message_size, int errnum,
int fildes, int request, void *data);
.SH DESCRIPTION
These functions may be used to obtain explanations for
errors returned by the \f[I]ioctl\fP(2) system call.
.\" ----------------------------------------------------
.SS explain_ioctl
const char *explain_ioctl(int fildes, int request, void *data);
.PP
The \f[B]explain_ioctl\fP function is
used to obtain an explanation of an error returned by the \f[I]ioctl\fP(2)
system call. The least the message will contain is the
value of \f[CW]strerror(errno)\fP, but usually it will
do much better, and indicate the underlying cause in more
detail.
.PP
The \f[I]errno\fP global variable will be used to obtain
the error value to be decoded.
.PP
This function is intended to be used in a fashion
similar to the following example:
.RS
.ft CW
.nf
int result = ioctl(fildes, request, data);
if (result < 0)
{
fprintf(stderr, "%s\en", explain_ioctl(fildes, request, data));
exit(EXIT_FAILURE);
}
.fi
.ft R
.RE
.PP
The above code example is available pre\[hy]packaged as the
\f[I]explain_ioctl_or_die\fP(3) function.
.TP 8n
\f[I]fildes\fP
The original fildes, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]request\fP
The original request, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]data\fP
The original data, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
Returns:
The message explaining the error. This message buffer is
shared by all libexplain functions which do not supply a
buffer in their argument list. This will be overwritten
by the next call to any libexplain function which shares
this buffer, including other threads.
.PP
\f[B]Note:\fP
This function is \f[B]not\fP thread safe, because it
shares a return buffer across all threads, and many other
functions in this library.
.\" ----------------------------------------------------
.SS explain_errno_ioctl
const char *explain_errno_ioctl(int errnum, int fildes, int request,
void *data);
.PP
The \f[B]explain_errno_ioctl\fP function
is used to obtain an explanation of an error returned by
the \f[I]ioctl\fP(2) system call.
The least the message will contain is the value of
\f[CW]strerror(errnum)\fP, but usually it will do much
better, and indicate the underlying cause in more detail.
.PP
This function is intended to be used in a fashion
similar to the following example:
.RS
.ft CW
.nf
if (ioctl(fildes, request, data) < 0)
{
int err = errno;
fprintf(stderr, "%s\en",
explain_errno_ioctl(err, fildes, request, data));
exit(EXIT_FAILURE);
}
.fi
.ft R
.RE
.PP
The above code example is available pre\[hy]packaged as the
\f[I]explain_ioctl_or_die\fP(3) function.
.TP 8n
\f[I]errnum\fP
The error value to be decoded, usually obtained from
the \f[I]errno\fP global variable just before this
function is called. This is necessary if you need to call
\f[B]any\fP code between the system call to be explained
and this function, because many libc functions will alter
the value of \f[I]errno\fP.
.TP 8n
\f[I]fildes\fP
The original fildes, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]request\fP
The original request, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]data\fP
The original data, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
Returns:
The message explaining the error. This message buffer is
shared by all libexplain functions which do not supply a
buffer in their argument list. This will be overwritten
by the next call to any libexplain function which shares
this buffer, including other threads.
.PP
\f[B]Note:\fP
This function is \f[B]not\fP thread safe, because it
shares a return buffer across all threads, and many other
functions in this library.
.\" ----------------------------------------------------
.SS explain_message_ioctl
void explain_message_ioctl(char *message, int message_size, int fildes,
int request, void *data);
.PP
The \f[B]explain_message_ioctl\fP
function may be used to obtain an explanation of an error
returned by the
\f[I]ioctl\fP(2) system call.
The least the message will contain is the value of
\f[CW]strerror(errno)\fP, but usually it will do much
better, and indicate the underlying cause in more detail.
.PP
The \f[I]errno\fP global variable will be used to obtain
the error value to be decoded.
.PP
This function is intended to be used in a fashion
similar to the following example:
.RS
.ft CW
.nf
if (ioctl(fildes, request, data) < 0)
{
char message[3000];
explain_message_ioctl(message, sizeof(message), fildes, request, data);
fprintf(stderr, "%s\en", message);
exit(EXIT_FAILURE);
}
.fi
.ft R
.RE
.PP
The above code example is available pre\[hy]packaged as the
\f[I]explain_ioctl_or_die\fP(3) function.
.TP 8n
\f[I]message\fP
The location in which to store the returned message.
If a suitable message return buffer is supplied, this
function is thread safe.
.TP 8n
\f[I]message_size\fP
The size in bytes of the location in which to
store the returned message.
.TP 8n
\f[I]fildes\fP
The original fildes, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]request\fP
The original request, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]data\fP
The original data, exactly as passed to the \f[I]ioctl\fP(2) system call.
.\" ----------------------------------------------------
.SS explain_message_errno_ioctl
void explain_message_errno_ioctl(char *message, int message_size, int errnum,
int fildes, int request, void *data);
.PP
The \f[B]explain_message_errno_ioctl\fP
function may be used to obtain an explanation of an error
returned by the
\f[I]ioctl\fP(2) system call.
The least the message will contain is the value of
\f[CW]strerror(errnum)\fP, but usually it will do much
better, and indicate the underlying cause in more detail.
.PP
This function is intended to be used in a fashion
similar to the following example:
.RS
.ft CW
.nf
if (ioctl(fildes, request, data) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_ioctl(message, sizeof(message), err,
fildes, request, data);
fprintf(stderr, "%s\en", message);
exit(EXIT_FAILURE);
}
.fi
.ft R
.RE
.PP
The above code example is available pre\[hy]packaged as the
\f[I]explain_ioctl_or_die\fP(3) function.
.TP 8n
\f[I]message\fP
The location in which to store the returned message.
If a suitable message return buffer is supplied, this
function is thread safe.
.TP 8n
\f[I]message_size\fP
The size in bytes of the location in which to
store the returned message.
.TP 8n
\f[I]errnum\fP
The error value to be decoded, usually obtained from
the \f[I]errno\fP global variable just before this
function is called. This is necessary if you need to call
\f[B]any\fP code between the system call to be explained
and this function, because many libc functions will alter
the value of \f[I]errno\fP.
.TP 8n
\f[I]fildes\fP
The original fildes, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]request\fP
The original request, exactly as passed to the \f[I]ioctl\fP(2) system call.
.TP 8n
\f[I]data\fP
The original data, exactly as passed to the \f[I]ioctl\fP(2) system call.
.\" ----------------------------------------------------
.SH SEE ALSO
.TP 8n
\f[I]ioctl\fP(2)
control device
.TP 8n
\f[I]explain_ioctl_or_die\fP(3)
control device and report errors
.\" ----------------------------------------------------
.SH COPYRIGHT
.lf 1 ./etc/version.so
.ds v) 1.4
.ds V) 1.4.D001
.ds Y) 2008, 2009, 2010, 2011, 2012, 2013, 2014
.lf 275 ./man/man3/explain_ioctl.3
.if n .ds C) (C)
.if t .ds C) \(co
libexplain version \*(v)
.br
Copyright \*(C) 2008 Peter Miller
.\" vim:ts=8:sw=4:et