PROFIL(2)                                                            PROFIL(2)



NAME
       profil - execution time profile

SYNOPSIS
       profil(buff, bufsiz, offset, scale)
       char *buff;
       int bufsiz, offset, scale;

DESCRIPTION
       _B_u_f_f points to an area of core whose length (in bytes) is given by _b_u_f_‐
       _s_i_z.  After this call, the user’s program counter (pc) is examined each
       clock  tick  (10  milliseconds);  _o_f_f_s_e_t is subtracted from it, and the
       result multiplied by _s_c_a_l_e.  If the resulting number corresponds  to  a
       word inside _b_u_f_f_, that word is incremented.

       The  scale  is interpreted as an unsigned, fixed-point fraction with 16
       bits of fraction: 0x10000 gives a 1-1 mapping of pc’s to words in _b_u_f_f_;
       0x8000 maps each pair of instruction words together.

       Profiling  is  turned  off by giving a _s_c_a_l_e of 0 or 1.  It is rendered
       ineffective by giving a _b_u_f_s_i_z of 0.  Profiling is turned off  when  an
       _e_x_e_c_v_e  is  executed,  but  remains on in child and parent both after a
       _f_o_r_k.  Profiling is turned off if an update in _b_u_f_f would cause a  mem‐
       ory fault.

RETURN VALUE
       A 0, indicating success, is always returned.

SEE ALSO
       gprof(1), setitimer(2), monitor(3)



4th Berkeley Distribution        May 14, 1986                        PROFIL(2)