profil(3) — Linux manual page

profil(3)               Library Functions Manual               profil(3)

NAME

       profil - execution time profile

LIBRARY

       Standard C library (libc, -lc)

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():
           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

       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

       Zero is always returned.

ATTRIBUTES

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌───────────────────────────────────┬───────────────┬───────────┐
       │ Interface                         │ Attribute     │ Value     │
       ├───────────────────────────────────┼───────────────┼───────────┤
       │ profil()                          │ Thread safety │ MT-Unsafe │
       └───────────────────────────────────┴───────────────┴───────────┘

STANDARDS

       None.

HISTORY

       Similar to a call in SVr4.

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.

SEE ALSO

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

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                      profil(3)

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

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