MONITOR(3C)         UNIX Programmer's Manual          MONITOR(3C)

NAME
     monitor - prepare execution profile

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

HP-UX COMPATIBILITY
     Level:    HP-UX/STANDARD

     Origin:   System III

     Remarks:  _M_o_n_i_t_o_r is implemented on the Series 200 only.

DESCRIPTION
     An  executable  program  created  by  cc  -p   automatically
     includes calls for _m_o_n_i_t_o_r with default parameters.  _M_o_n_i_t_o_r
     needn't be called explicitly except  to  gain  fine  control
     over profiling.

     _M_o_n_i_t_o_r is an interface to _p_r_o_f_i_l(2).  _L_o_w_p_c and _h_i_g_h_p_c  are
     the  addresses of two functions.  _B_u_f_f_e_r is the address of a
     (user supplied) array of _b_u_f_s_i_z_e  short  integers.   _M_o_n_i_t_o_r
     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 sam-
     pled is that of _l_o_w_p_c and the highest is just below  _h_i_g_h_p_c.
     At  most _n_f_u_n_c call counts can be kept.  Only calls of func-
     tions compiled with the profiling option  -p  of  _c_c(1)  are
     recorded.   For  the  results  to be significant, especially
     where there are small, heavily used  routines,  it  is  sug-
     gested  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);

     _E_t_e_x_t lies just above all the program text (see _e_n_d(3C)).

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

          monitor(0);

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

FILES
     mon.out

SEE ALSO
     cc(1), prof(1), profil(2).