NAME

monitor − prepare execution profile

SYNOPSIS

monitor (lowpc, highpc, buffer, bufsize, nfunc)
int (∗lowpc)( ), (∗highpc)( );
short buffer[ ];
int bufsize, nfunc;

DESCRIPTION

An executable program created by cc −p automatically includes calls for monitor with default parameters; monitor needn’t 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 short integers.  Monitor arranges to record a histogram of periodically sampled values of the program counter, and of counts of calls of certain functions, in the buffer.  The lowest address sampled is that of lowpc and the highest is just below highpc. At most nfunc call counts can be kept; only calls of functions compiled with the profiling option −p of cc(1) are recorded. For the 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(2, etext, buf, bufsize, nfunc);

Etext lies just above all the program text, see end(3C).

To stop execution monitoring and write the results on the file mon.out, use

monitor(0);

prof(1) can then be used to examine the results.

FILES

mon.out

SEE ALSO

cc(1), prof(1), profil(2). 

May 16, 1980