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

NAME         top

       profil - execution time profile

SYNOPSIS         top

       #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)):

           Since glibc 2.21:
           In glibc 2.19 and 2.20:
               _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
           Up to and including glibc 2.19:
               _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION         top

       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         top

       Zero is always returned.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface Attribute     Value     │
       │profil()  │ Thread safety │ MT-Unsafe │

CONFORMING TO         top

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

BUGS         top

       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         top

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

COLOPHON         top

       This page is part of release 4.13 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

Linux                            2017-09-15                        PROFIL(3)

Pages that refer to this page: syscalls(2)unimplemented(2)