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)