profil(3) — Linux manual page

profil(3)                Library Functions Manual               profil(3)

NAME         top

       profil - execution time profile

LIBRARY         top

       Standard C library (libc, -lc)

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)):

       profil():
           Since glibc 2.21:
               _DEFAULT_SOURCE
           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
       attributes(7).
       ┌────────────────────────────────────┬───────────────┬───────────┐
       │ Interface                          │ Attribute     │ Value     │
       ├────────────────────────────────────┼───────────────┼───────────┤
       │ profil()                           │ Thread safety │ MT-Unsafe │
       └────────────────────────────────────┴───────────────┴───────────┘

STANDARDS         top

       None.

HISTORY         top

       Similar to a call in SVr4.

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.

SEE ALSO         top

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

COLOPHON         top

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Linux man-pages 6.15            2025-05-17                      profil(3)

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

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