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():
           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 │
       └──────────┴───────────────┴───────────┘

CONFORMING TO

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

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

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