PROFIL(2-BSD)       RISC/os Reference Manual        PROFIL(2-BSD)



NAME
     profil - execution time profile

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

DESCRIPTION
     buff points to an area of core whose length (in bytes) is
     given by bufsiz.  After this call, the user's program
     counter (pc) is examined each clock tick (10 milliseconds);
     offset is subtracted from it, and the result multiplied by
     scale.  If the resulting number corresponds to a word inside
     buff, that word is incremented.

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

     Profiling is turned off by giving a scale of 0 or 1.  It is
     rendered ineffective by giving a bufsiz of 0.  Profiling is
     turned off when an execve is executed, but remains on in
     child and parent both after a fork.  Profiling is turned off
     if an update in buff would cause a memory fault.

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

SEE ALSO
     getitimer(2), monitor(3).























                        Printed 11/19/92                   Page 1