profil − execution time profile
int profil(u_short *buf, size_t bufsiz, size_t offset, u_int scale);
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.
Zero is always returned.
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.
Similar to a call in SVr4 (but not POSIX.1).