NAME
monitor() — prepare execution profile
SYNOPSIS
#include <mon.h>
void monitor(
void (*lowpc)(),
void (*highpc)(),
WORD *buffer,
int bufsize,
int nfunc
);
DESCRIPTION
An executable program created by
cc -p
automatically includes calls for
monitor()
with default parameters;
monitor()
need not be called explicitly
except to gain fine control over profiling.
monitor()
is an interface to
profil(2).
lowpc
and
highpc
are the addresses of two functions;
buffer
is the address of a (user-supplied) array of
bufsize
WORDs
(defined in the
<mon.h>
header file).
monitor()
arranges to record in the buffer a histogram
of periodically sampled values of the program counter,
and of counts of calls of certain functions.
The lowest address sampled is that of
lowpc
and the highest is just below
highpc.
lowpc
must not equal 0 for this use of
monitor.
Not more than
nfunc
call counts can be kept;
only calls of functions compiled with the profiling option
-p
of
cc(1)
are recorded.
(The C Library and Math Library supplied when
cc -p
is used also have call counts recorded.)
For results to be significant, especially where there are small,
heavily used routines, it is suggested that the buffer
be no more than a few times smaller than the range of locations sampled.
To profile the entire program, it is sufficient to use
extern etext;
...
monitor ((int (*)())2, ((int(*)())& etext, buf, bufsize, nfunc);
etext
lies just above all the program text (see
end(3C)).
To stop execution monitoring and write the results on file
mon.out,
use
monitor ((int (*)())0, (int(*)())0, 0, 0, 0);
prof(1)
can then be used to examine the results.
FILES
/usr/lib/libc.a
/usr/lib/libm.a
mon.out
STANDARDS CONFORMANCE
monitor(): SVID2, SVID3, XPG2
