.lf 1 ./man/man3/explain_sethostname.3
.\"
.\" libexplain - Explain errno values returned by libc functions
.\" Copyright (C) 2009-2011 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.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with this program. If not, see .
.\"
.ds n) explain_sethostname
.cp 0 \" Solaris defaults to ''.cp 1'', sheesh.
.TH explain_sethostname 3
.SH NAME
explain_sethostname \- explain sethostname(2) errors
.if require_index \{
.\}
.SH SYNOPSIS
#include
.sp 0.3
const char *explain_sethostname(const char *name, size_t name_size);
.br
const char *explain_errno_sethostname(int errnum, const char *name,
size_t name_size);
.br
void explain_message_sethostname(char *message, int message_size,
const char *name, size_t name_size);
.br
void explain_message_errno_sethostname(char *message, int message_size,
int errnum, const char *name, size_t name_size);
.SH DESCRIPTION
These functions may be used to obtain explanations for errors returned by
the \f[I]sethostname\fP(2) system call.
.\" ----------------------------------------------------
.SS explain_sethostname
const char *explain_sethostname(const char *name, size_t name_size);
.PP
The \f[B]explain_sethostname\fP function is used to obtain an explanation
of an error returned by the \f[I]sethostname\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 (sethostname(name, name_size) < 0)
{
fprintf(stderr, "%s\en", explain_sethostname(name, name_size));
exit(EXIT_FAILURE);
}
.fi
.ft R
.RE
.PP
The above code example is available pre\[hy]packaged as the
\f[I]explain_sethostname_or_die\fP(3) function.
.TP 8n
\f[I]name\fP
The original name, exactly as passed to the \f[I]sethostname\fP(2) system
call.
.TP 8n
\f[I]name_size\fP
The original name_size, exactly as passed to the \f[I]sethostname\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_sethostname
const char *explain_errno_sethostname(int errnum, const char *name,
size_t name_size);
.PP
The \f[B]explain_errno_sethostname\fP function is used to obtain an
explanation of an error returned by the \f[I]sethostname\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
This function is intended to be used in a fashion similar to the following
example:
.RS
.ft CW
.nf
if (sethostname(name, name_size) < 0)
{
int err = errno;
fprintf(stderr, "%s\en", explain_errno_sethostname(err, name, name_size));
exit(EXIT_FAILURE);
}
.fi
.ft R
.RE
.PP
The above code example is available pre\[hy]packaged as the
\f[I]explain_sethostname_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]name\fP
The original name, exactly as passed to the \f[I]sethostname\fP(2) system
call.
.TP 8n
\f[I]name_size\fP
The original name_size, exactly as passed to the \f[I]sethostname\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_sethostname
void explain_message_sethostname(char *message, int message_size,
const char *name, size_t name_size);
.PP
The \f[B]explain_message_sethostname\fP function is used to obtain an
explanation of an error returned by the \f[I]sethostname\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 (sethostname(name, name_size) < 0)
{
char message[3000];
explain_message_sethostname(message, sizeof(message), name, name_size);
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_sethostname_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]name\fP
The original name, exactly as passed to the \f[I]sethostname\fP(2) system
call.
.TP 8n
\f[I]name_size\fP
The original name_size, exactly as passed to the \f[I]sethostname\fP(2)
system call.
.\" ----------------------------------------------------
.SS explain_message_errno_sethostname
void explain_message_errno_sethostname(char *message, int message_size,
int errnum, const char *name, size_t name_size);
.PP
The \f[B]explain_message_errno_sethostname\fP function is used to obtain an
explanation of an error returned by the \f[I]sethostname\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
This function is intended to be used in a fashion similar to the following
example:
.RS
.ft CW
.nf
if (sethostname(name, name_size) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_sethostname(message, sizeof(message), err, name,
name_size);
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_sethostname_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]name\fP
The original name, exactly as passed to the \f[I]sethostname\fP(2) system
call.
.TP 8n
\f[I]name_size\fP
The original name_size, exactly as passed to the \f[I]sethostname\fP(2)
system call.
.\" ----------------------------------------------------
.SH SEE ALSO
.TP 8n
\f[I]sethostname\fP(2)
get/set hostname
.TP 8n
\f[I]explain_sethostname_or_die\fP(3)
get/set hostname 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 251 ./man/man3/explain_sethostname.3
.if n .ds C) (C)
.if t .ds C) \(co
libexplain version \*(v)
.br
Copyright \*(C) 2009 Peter Miller
.\" vim: set ts=8 sw=4 et