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



NAME
       profil - execution time profile

SYNOPSIS
       #include <unistd.h>

       int profil(unsigned short *buf, size_t bufsiz,
                  size_t offset, unsigned int scale);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       profil(): _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

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 multi‐
       plied 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.

CONFORMING TO
       Similar to a call in SVr4 (but not POSIX.1-2001).

BUGS
       profil()  cannot  be  used  on  a  program that also uses ITIMER_PROF interval timers (see
       setitimer(2)).

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

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

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2014-07-08                                  PROFIL(3)