profil - execution time profile
int profil(unsigned short *buf, size_t bufsiz,
size_t offset, unsigned int scale);
Feature Test Macro Requirements for glibc (see feature_test_macros
Since glibc 2.21:
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)
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:
is subtracted and the result is multiplied by scale
divided by 65536. If the resulting value is less than bufsiz
, then the
corresponding entry in buf
is incremented. If buf
profiling is disabled.
Zero is always returned.
For an explanation of the terms used in this section, see attributes
Similar to a call in SVr4 (but not POSIX.1).
() cannot be used on a program that also uses ITIMER_PROF
interval timers (see setitimer
True kernel profiling provides more accurate results. Libc 4.4 contained a
kernel patch providing a system call profil.