profil


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 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, profil-
       ing 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 inter-
       val timers (see setitimer(2)).

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

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

COLOPHON
       This  page  is  part of release 3.54 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux                             2007-07-26                         PROFIL(3)
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