1PROFIL(3)                  Linux Programmer's Manual                 PROFIL(3)
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NAME

6       profil - execution time profile
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SYNOPSIS

9       #include <unistd.h>
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11       int profil(unsigned short *buf, size_t bufsiz,
12                  size_t offset, unsigned int scale);
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14   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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16       profil():
17           Since glibc 2.21:
18               _DEFAULT_SOURCE
19           In glibc 2.19 and 2.20:
20               _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
21           Up to and including glibc 2.19:
22               _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
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DESCRIPTION

25       This  routine  provides  a means to find out in what areas your program
26       spends most of its time.  The argument buf points to  bufsiz  bytes  of
27       core.   Every  virtual 10 milliseconds, the user's program counter (PC)
28       is examined: offset is subtracted and the result is multiplied by scale
29       and divided by 65536.  If the resulting value is less than bufsiz, then
30       the corresponding entry in buf is incremented.  If buf is NULL, profil‐
31       ing is disabled.
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RETURN VALUE

34       Zero is always returned.
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ATTRIBUTES

37       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
38       tributes(7).
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40       ┌──────────────────────────────────────────┬───────────────┬───────────┐
41       │Interface                                 │ Attribute     │ Value     │
42       ├──────────────────────────────────────────┼───────────────┼───────────┤
43       │profil()                                  │ Thread safety │ MT-Unsafe │
44       └──────────────────────────────────────────┴───────────────┴───────────┘
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CONFORMING TO

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

50       profil() cannot be used on a program that also uses ITIMER_PROF  inter‐
51       val timers (see setitimer(2)).
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53       True kernel profiling provides more accurate results.
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SEE ALSO

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

59       This  page  is  part of release 5.12 of the Linux man-pages project.  A
60       description of the project, information about reporting bugs,  and  the
61       latest     version     of     this    page,    can    be    found    at
62       https://www.kernel.org/doc/man-pages/.
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66Linux                             2021-03-22                         PROFIL(3)
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