ultrix man page for monstartup

monitor(3)						     Library Functions Manual							monitor(3)

Name
       monitor, monstartup, moncontrol - prepare execution profile

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

       monstartup(lowpc, highpc)
       int (*lowpc)(), (*highpc)();

       moncontrol(mode)

Description
       These functions use the system call to control program-counter sampling.  Using the option -p when compiling or linking a program automati-
       cally generates calls to these functions.  You do need not to call these functions explicitly unless you want more control.

       Typically, you would call either or to initialize pc-sampling and enable it; call to disable or reenable it; and call at the end of  execu-
       tion to disable sampling and record the samples in a file.

       Your  initial  call  to	enables  pc-sampling.	The  parameters lowpc and highpc specify the range of addresses to be sampled.	The lowest
       address is that of lowpc and the highest is just below highpc.  The buffer parameter is the address of a (user allocated) array of  bufsize
       short  integers,  which	holds  a  record of the samples; for best results, the buffer should not be less than a few times smaller than the
       range of addresses sampled.  The nfunc parameter is ignored.

       The environment variable PROFDIR determines the name of the output file and whether pc-sampling takes place: if it is not set, the file	is
       named  mon.out;	if  set  to  the empty string, no pc-sampling occurs; if set to a non-empty string, the file is named string/pid.progname,
       where pid is the process id of the executing program and progname is the program's name as it appears in argv[0]. The  subdirectory  string
       must already exist.

       To profile the entire program, use the following:

	    extern eprol(), etext();
	    . . .
	    monitor(eprol, etext, buf, bufsize, 0);

       The  routine  lies just below the user program text, and lies just above it, as described in (Because the user program does not necessarily
       start at a low memory address, using a small number in place of is dangerous).

       The routine is an alternate form of that calls (see for you to allocate the buffer.

       The function selectively disables and re-enables pc-sampling within a program, allowing you to measure the cost of  particular  operations.
       The function disables pc-sampling, and reenables it.

       To stop execution monitoring and write the results in the output file, use the following:

	    monitor(0);

Files
       mon.out	     default name for output file
       libprof1.a    routines for pc-sampling

See Also
       cc(1), ld(1), profil(2), brk(2)

								       RISC								monitor(3)