.TH LIBPFM 3 "November, 2003" "" "Linux Programmer's Manual"
.SH NAME
pfm_set_options \- set performance monitoring library debug options
.SH SYNOPSIS
.nf
.B #include <perfmon/pfmlib.h>
.sp
.BI "int pfm_set_options(pfmlib_options_t *"opt);
.sp
.SH DESCRIPTION
This function can be called at any time to adjust the level
of debug of the library. In both cases, extra output will be
generated on standard error when the library gets
called. This can be useful to figure out how the PMC
registers are initialized for instance.
.sp
The opt argument to this function is a pointer to a 
.B pfmlib_options_t 
structure which is defined as follows:
.sp
.nf 
typedef struct {
	unsigned int	pfm_debug:1;
	unsigned int	pfm_verbose:1;
} pfmlib_options_t;
.fi
.sp
.sp
Setting \fBpfm_debug\fR to 1 will enable debug messages whereas setting
\fBpfm_verbose\fR will enable verbose messages. 

.SH ENVIRONMENT VARIABLES
Setting library options with this function has lower priority than
with environment variables. As such, the call to this function may
not have any actual effects. A user can set the following environment
variables to control verbosity and debug output:
.TP
.B LIBPFM_VERBOSE
Enable verbose output. Value must be 0 or 1. When not set, verbosity level
can be controlled with this function.
.TP
.B LIBPFM_DEBUG
Enable debug  output. Value must be 0 or 1. When not set, debug level
can be controlled with this function.
.LP
.SH RETURN
The function returns whether or not it was successful. A return
value of \fBPFMLIB_SUCCESS\fR indicates success, otherwise the 
value is the error code.
.sp
When environment variables exist, they take precedence and this
function returns \fBPFMLIB_SUCCESS\fR.
.SH ERRORS
.TP
.B PFMLIB_ERR_INVAL 
the argument is invalid, most likely a NULL pointer.
.SH AUTHOR
Stephane Eranian <eranian@hpl.hp.com>
.PP