profil (3) - Linux Man Pages
profil: execution time profile
profil - execution time profile
#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)):
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)
DESCRIPTIONThis 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 VALUEZero is always returned.
ATTRIBUTESFor an explanation of the terms used in this section, see attributes(7).
CONFORMING TOSimilar to a call in SVr4 (but not POSIX.1).
BUGSprofil() 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.
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