.\"	$NetBSD: kvm_getlwps.3,v 1.7.8.1 2018/02/03 22:13:26 snj Exp $
.\"
.\"Copyright (c) 2002 The NetBSD Foundation, Inc.
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.\"This code is derived from software contributed to The NetBSD Foundation
.\"by Nathan J. Williams.
.\"
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.\"modification, are permitted provided that the following conditions
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.Dd January 9, 2018
.Dt KVM_GETLWPS 3
.Os
.Sh NAME
.Nm kvm_getlwps
.Nd access state of LWPs belonging to a user process
.Sh LIBRARY
.Lb libkvm
.Sh SYNOPSIS
.In kvm.h
.In sys/param.h
.In sys/sysctl.h
.\" .Fa kvm_t *kd
.Ft struct kinfo_lwp *
.Fn kvm_getlwps "kvm_t *kd" "int pid" "unsigned long procaddr" "size_t elemsize" "int *cnt"
.Sh DESCRIPTION
.Fn kvm_getlwps
returns the set of LWPs belonging to the process specified by
.Fa pid
or
.Fa procaddr
in the kernel indicated by
.Fa kd .
The number of LWPs found is returned in the reference parameter
.Fa cnt .
The LWPs are returned as a contiguous array of
.Sy kinfo_lwp
structures.
This memory is locally allocated, and subsequent calls to
.Fn kvm_getlwps
and
.Fn kvm_close
will overwrite this storage.
.Pp
Only the first
.Fa elemsize
bytes of each array entry are returned.
If the size of the
.Sy kinfo_lwp
structure increases in size in a future release of
.Nx
the kernel will only return the requested amount of data for
each array entry and programs that use
.Fn kvm_getlwps
will continue to function without the need for recompilation.
.Pp
If called against an active kernel, the
.Fn kvm_getlwps
function will use the
.Xr sysctl 3
interface and return information about the process identified by
.Fa pid ;
otherwise the kernel memory device file or swap device will be
accessed and the process is identified by the location passed in
.Fa paddr .
.Sh RETURN VALUES
.Fn kvm_getlwps
returns
.Dv NULL
on failure.
.Sh SEE ALSO
.Xr kvm 3 ,
.Xr kvm_close 3 ,
.Xr kvm_geterr 3 ,
.Xr kvm_getproc2 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
These routines do not belong in the kvm interface.