redhat man page for profil

PROFIL(3)						     Linux Programmer's Manual							 PROFIL(3)

NAME
       profil - execution time profile

SYNOPSIS
       #include <unistd.h>

       int profil(u_short *buf, size_t bufsiz, size_t offset, u_int scale);

DESCRIPTION
       This  routine  provides	a means to find out in what areas your program spends most of its time. The argument buf points to bufsiz bytes of
       core.  Every virtual 10 milliseconds, the user's program counter (PC) is examined: offset is subtracted and the	result	is  multiplied	by
       scale  and  divided  by	65536.	If the resulting value is less than bufsiz, then the corresponding entry in buf is incremented.  If buf is
       NULL, profiling is disabled.

RETURN VALUE
       Zero is always returned.

BUGS
       profil cannot be used on a program that also uses ITIMER_PROF itimers.

       True kernel profiling provides more accurate results.  Libc 4.4 contained a kernel patch providing a system call profil.

CONFORMING TO
       Similar to a call in SVr4 (but not POSIX.1).

SEE ALSO
       gprof(1), setitimer(2), signal(2), sigaction(2)

Linux 2.0							    1993-07-23								 PROFIL(3)