'\" te
.\" Copyright (c) 2005, Sun Microsystems, Inc. All Rights Reserved.
.TH cpc_access 3CPC "28 Mar 2005" "SunOS 5.11" "CPU Performance Counters Library Functions"
.SH NAME
cpc_access \- test access CPU performance counters
.SH SYNOPSIS
.LP
.nf
cc [ \fIflag\fR... ] \fIfile\fR... \(milcpc [ \fIlibrary\fR... ]
#include <libcpc.h>

\fBint\fR \fBcpc_access\fR(\fBvoid\fR);
.fi

.SH DESCRIPTION
.sp
.LP
Access to CPU performance counters is possible only on systems where the appropriate hardware exists and is correctly configured. The \fBcpc_access()\fR function \fBmust\fR be used to determine if the hardware exists and is accessible on the platform before any of the interfaces that use the counters are invoked.
.sp
.LP
When the hardware is available, access to the per-process counters is always allowed to the process itself, and allowed to other processes mediated using the existing security mechanisms of \fB/proc\fR. 
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBcpc_access()\fR returns \fB0\fR.  Otherwise, it returns \fB\(mi1\fR and sets \fBerrno\fR to indicate the error.
.sp
.LP
By default, two common \fBerrno\fR values are decoded and cause the library to print an error message using its reporting mechanism. See \fBcpc_seterrfn\fR(3CPC) for a description of how this behavior can be modified.
.SH ERRORS
.sp
.LP
The \fBcpc_access()\fR function will fail if:
.sp
.ne 2
.mk
.na
\fB\fBEAGAIN\fR\fR
.ad
.RS 10n
.rt  
Another process may be sampling system-wide CPU statistics.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOSYS\fR\fR
.ad
.RS 10n
.rt  
CPU performance counters are inaccessible on this machine. This error can occur when the machine supports CPU performance counters, but some software components are missing. Check to see that all CPU Performance Counter packages have been correctly installed.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
lw(2.75i) |lw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
MT-LevelMT-Safe
_
Interface StabilityObsolete
.TE

.SH SEE ALSO
.sp
.LP
\fBcpc\fR(3CPC), \fBcpc_open\fR(3CPC), \fBcpc_seterrfn\fR(3CPC), \fBlibcpc\fR(3LIB), \fBproc\fR(4), \fBattributes\fR(5)
.SH NOTES
.sp
.LP
The \fBcpc_access()\fR function exists for binary compatibility only. Source containing this function will not compile. This function is obsolete and might be removed in a future release. Applications should use \fBcpc_open\fR(3CPC) instead.