posix man page for profil

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

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
       This page is part of release 4.15 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 https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15								 PROFIL(3)