freebsd-dev/lib/libkvm/kvm_geterr.3

.\" Copyright (c) 1992, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software developed by the Computer Systems
.\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract
.\" BG 91-66 and contributed to Berkeley.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" 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
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)kvm_geterr.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd March 21, 2017
.Dt KVM_GETERR 3
.Os
.Sh NAME
.Nm kvm_geterr
.Nd get error message on kvm descriptor
.Sh LIBRARY
.Lb libkvm
.Sh SYNOPSIS
.In kvm.h
.Ft char *
.Fn kvm_geterr "kvm_t *kd"
.Sh DESCRIPTION
This function returns a string describing the most recent error condition
on the descriptor
.Fa kd .
The results are undefined if the most recent
.Xr kvm 3
library call did not produce an error.
The string returned is stored in memory owned by
.Xr kvm 3
so the message should be copied out and saved elsewhere if necessary.
.Sh RETURN VALUES
The function
.Fn kvm_geterr
will return "" if
.Fa kd
is
.Dv NULL
or an error has not been captured for
.Fa kd .
.Sh SEE ALSO
.Xr kvm 3 ,
.Xr kvm_close 3 ,
.Xr kvm_getargv 3 ,
.Xr kvm_getenvv 3 ,
.Xr kvm_getprocs 3 ,
.Xr kvm_nlist 3 ,
.Xr kvm_open 3 ,
.Xr kvm_openfiles 3 ,
.Xr kvm_read 3 ,
.Xr kvm_write 3
.Sh BUGS
This routine cannot be used to access error conditions due to a failed
.Fn kvm_openfiles
call, since failure is indicated by returning a
.Dv NULL
descriptor.
Therefore, errors on open are output to the special error buffer
passed to
.Fn kvm_openfiles .
This option is not available to
.Fn kvm_open .
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" Copyright (c) 1992, 1993`
			`.\" The Regents of the University of California. All rights reserved.`
			`.\"`
			`.\" This code is derived from software developed by the Computer Systems`
			`.\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract`
			`.\" BG 91-66 and contributed to Berkeley.`
			`.\"`
			`.\" Redistribution and use in source and binary forms, with or without`
			`.\" 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`
			`.\" documentation and/or other materials provided with the distribution.`
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96 2017-02-28 23:42:47 +00:00			`.\" 3. Neither the name of the University nor the names of its contributors`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\" may be used to endorse or promote products derived from this software`
			`.\" without specific prior written permission.`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
			`.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
			`.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE`
			`.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE`
			`.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
			`.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS`
			`.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)`
			`.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT`
			`.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY`
			`.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`.\" SUCH DAMAGE.`
			`.\"`
			`.\" @(#)kvm_geterr.3 8.1 (Berkeley) 6/4/93`
$Id$ -> $FreeBSD$ 1999-08-28 00:22:10 +00:00			`.\" $FreeBSD$`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.\"`
kvm_geterr: handle `kd` == NULL in a deterministic/graceful manner Return a NUL string instead of just working by accident with kvm_geterr(3) when MALLOC_PRODUCTION is disabled (I didn't confirm the MALLOC_PRODUCTION being enabled path). Document the new explicit return behavior for kvm_geterr(3), as well as the previous implicit behavior, i.e., the buffer attached to returned via kvm_geterr(3) would be empty if a previous error hadn't been stored in `kd`. Differential Revision: D10022 MFC after: 1 week Reviewed by: vangyzen Sponsored by: Dell EMC Isilon 2017-03-21 19:02:17 +00:00			`.Dd March 21, 2017`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Dt KVM_GETERR 3`
			`.Os`
			`.Sh NAME`
			`.Nm kvm_geterr`
			`.Nd get error message on kvm descriptor`
Introduce .Lb macro to libkvm manpages. Use .Pa macro for "enlighting" path 2000-04-22 16:10:12 +00:00			`.Sh LIBRARY`
			`.Lb libkvm`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh SYNOPSIS`
mdoc(7) police: Use the new .In macro for #include statements. 2001-10-01 16:09:29 +00:00			`.In kvm.h`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Ft char *`
			`.Fn kvm_geterr "kvm_t *kd"`
			`.Sh DESCRIPTION`
			`This function returns a string describing the most recent error condition`
			`on the descriptor`
			`.Fa kd .`
			`The results are undefined if the most recent`
			`.Xr kvm 3`
			`library call did not produce an error.`
Remove whitespace at EOL. 2001-07-15 07:53:42 +00:00			`The string returned is stored in memory owned by`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Xr kvm 3`
			`so the message should be copied out and saved elsewhere if necessary.`
kvm_geterr: handle `kd` == NULL in a deterministic/graceful manner Return a NUL string instead of just working by accident with kvm_geterr(3) when MALLOC_PRODUCTION is disabled (I didn't confirm the MALLOC_PRODUCTION being enabled path). Document the new explicit return behavior for kvm_geterr(3), as well as the previous implicit behavior, i.e., the buffer attached to returned via kvm_geterr(3) would be empty if a previous error hadn't been stored in `kd`. Differential Revision: D10022 MFC after: 1 week Reviewed by: vangyzen Sponsored by: Dell EMC Isilon 2017-03-21 19:02:17 +00:00			`.Sh RETURN VALUES`
			`The function`
			`.Fn kvm_geterr`
			`will return "" if`
			`.Fa kd`
			`is`
			`.Dv NULL`
			`or an error has not been captured for`
			`.Fa kd .`
BSD 4.4 Lite Lib Sources 1994-05-27 05:00:24 +00:00			`.Sh SEE ALSO`
			`.Xr kvm 3 ,`
			`.Xr kvm_close 3 ,`
			`.Xr kvm_getargv 3 ,`
			`.Xr kvm_getenvv 3 ,`
			`.Xr kvm_getprocs 3 ,`
			`.Xr kvm_nlist 3 ,`
			`.Xr kvm_open 3 ,`
			`.Xr kvm_openfiles 3 ,`
			`.Xr kvm_read 3 ,`
			`.Xr kvm_write 3`
Sort sections. 2005-01-20 09:17:07 +00:00			`.Sh BUGS`
			`This routine cannot be used to access error conditions due to a failed`
			`.Fn kvm_openfiles`
			`call, since failure is indicated by returning a`
			`.Dv NULL`
			`descriptor.`
			`Therefore, errors on open are output to the special error buffer`
			`passed to`
			`.Fn kvm_openfiles .`
			`This option is not available to`
			`.Fn kvm_open .`