xref: /freebsd/lib/libkvm/kvm_getpcpu.3 (revision 794a9a6c96abe0413fbaf3a7f116e0a0e84e0e85)

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.Dd August 19, 2008
.Dt KVM_GETPCPU 3
.Os
.Sh NAME
.Nm kvm_getmaxcpu ,
.Nm kvm_getpcpu
.Nd access per-CPU data
.Sh LIBRARY
.Lb libkvm
.Sh SYNOPSIS
.In sys/param.h
.In sys/pcpu.h
.In sys/sysctl.h
.In kvm.h
.Ft int
.Fn kvm_getmaxcpu "kvm_t *kd"
.Ft void *
.Fn kvm_getpcpu "kvm_t *kd" "int cpu"
.Sh DESCRIPTION
The
.Fn kvm_getmaxcpu
and
.Fn kvm_getpcpu
functions are used to access the per-CPU data of active processors in the
kernel indicated by
.Fa kd .
The
.Fn kvm_getmaxcpu
function returns the maximum number of CPUs supported by the kernel.
The
.Fn kvm_getpcpu
function returns a buffer holding the per-CPU data for a single CPU.
This buffer is described by the
.Vt "struct pcpu"
type.
The caller is responsible for releasing the buffer via a call to
.Xr free 3
when it is no longer needed.
If
.Fa cpu
is not active, then
.Dv NULL
is returned instead.
.Sh RETURN VALUES
On success, the
.Fn kvm_getmaxcpu
function returns the maximum number of CPUs supported by the kernel.
If an error occurs,
it returns -1 instead.
.Pp
On success, the
.Fn kvm_getpcpu
function returns a pointer to an allocated buffer or
.Dv NULL.
If an error occurs,
it returns -1 instead.
.Pp
If either function encounters an error,
then an error message may be retrieved via
.Xr kvm_geterr 3.
.Sh SEE ALSO
.Xr free 3 ,
.Xr kvm 3