freebsd-nq/lib/libpmc/pmc_configure_logfile.3

.\" Copyright (c) 2007 Joseph Koshy.  All rights reserved.
.\"
.\" 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.
.\"
.\" This software is provided by Joseph Koshy ``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 Joseph Koshy 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.
.\"
.\" $FreeBSD$
.\"
.Dd November 24, 2007
.Dt PMC_CONFIGURE_LOGFILE 3
.Os
.Sh NAME
.Nm pmc_configure_logfile ,
.Nm pmc_flush_logfile ,
.Nm pmc_writelog ,
.Nm pmc_close_logfile
.Nd log file management
.Sh LIBRARY
.Lb libpmc
.Sh SYNOPSIS
.In pmc.h
.Ft int
.Fn pmc_configure_logfile "int fd"
.Ft int
.Fn pmc_flush_logfile void
.Ft int
.Fn pmc_writelog "uint32_t userdata"
.Ft int
.Fn pmc_close_logfile void
.Sh DESCRIPTION
The functions manage logging of
.Xr hwpmc 4
events.
.Pp
Function
.Fn pmc_configure_logfile
is used to turn on and turn off logging.
If argument
.Fa fd
is a valid file handle returned by a prior call to
.Xr open 2
or
.Xr socket 2
then performance events will be logged to the file corresponding
to the specified handle.
If the value of argument
.Fa fd
is -1 then logging will be stopped after any pending data is flushed.
.Pp
Function
.Fn pmc_flush_logfile
will force all log data queued inside the
.Xr hwpmc 4
driver to be written out.
.Pp
Function
.Fn pmc_writelog
will append a log entry containing the value of argument
.Fa userdata
to the log file.
.Pp
Function
.Fn pmc_close_logfile
will flush all pending log data and close
.Xr hwpmc 4 Ns Ap s
side of the stream.
.Sh RETURN VALUES
.Rv -std
.Sh ERRORS
A call to
.Fn pmc_configure_logfile
may fail with the following errors:
.Bl -tag -width Er
.It Bq Er EAGAIN
The
.Xr hwpmc 4
driver was not able to create a helper process due to system limits
being reached.
.It Bq Er EBUSY
Function
.Fn pmc_configure_logfile
was called with a log file already configured.
.It Bq Er EINVAL
Function
.Fn pmc_configure_logfile
was called with an argument of -1 without a log file being previously
configured.
.It Bq Er ENOMEM
The system encountered a memory shortage when servicing this request.
.El
.Pp
A call to
.Fn pmc_flush_logfile
may fail with the following errors:
.Bl -tag -width Er
.It Bq Er EINVAL
Function
.Fn pmc_flush_logfile
was called without a log file being previously configured.
.El
.Pp
A call to
.Fn pmc_writelog
may fail with the following errors:
.Bl -tag -width Er
.It Bq Er EINVAL
Function
.Fn pmc_writelog
was called without a log file being previously configured.
.It Bq Er ENOMEM
The system encountered a memory shortage when servicing this
request.
.El
.Sh SEE ALSO
.Xr pmc 3 ,
.Xr hwpmc 4