An executable program compiled using the
-pg
option to
cc(1)
automatically includes calls to collect statistics for the
gprof(1)
call-graph execution profiler.
In typical operation, profiling begins at program startup
and ends when the program calls exit.
When the program exits, the profiling data are written to the file
progname .gmon,
where progname is the name of the program, then
gprof(1)
can be used to examine the results.
The
moncontrol()
function
selectively controls profiling within a program.
When the program starts, profiling begins.
To stop the collection of histogram ticks and call counts use
moncontrol();
to resume the collection of histogram ticks and call counts use
moncontrol(1).
This feature allows the cost of particular operations to be measured.
Note that an output file will be produced on program exit
regardless of the state of
moncontrol().
Programs that are not loaded with
-pg
may selectively collect profiling statistics by calling
monstartup()
with the range of addresses to be profiled.
The
lowpc
and
highpc
arguments
specify the address range that is to be sampled;
the lowest address sampled is that of
lowpc
and the highest is just below
highpc.
Only functions in that range that have been compiled with the
-pg
option to
cc(1)
will appear in the call graph part of the output;
however, all functions in that address range will
have their execution time measured.
Profiling begins on return from
monstartup().
