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CLOCK(3) FreeBSD Library Functions Manual CLOCK(3)
NAME
clock - determine processor time used
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <time.h>
clock_t
clock(void);
DESCRIPTION
The clock() function determines the amount of processor time used since
the invocation of the calling process, measured in CLOCKS_PER_SECs of a
second.
RETURN VALUES
The clock() function returns the amount of time used unless an error
occurs, in which case the return value is -1.
SEE ALSO
getrusage(2), clocks(7)
STANDARDS
The clock() function conforms to ISO/IEC 9899:1990 ("ISO C90"). However,
Version 2 of the Single UNIX Specification ("SUSv2") requires
CLOCKS_PER_SEC to be defined as one million. FreeBSD does not conform to
this requirement; changing the value would introduce binary
incompatibility and one million is still inadequate on modern processors.
FreeBSD 14.0-RELEASE-p11 June 4, 1993 FreeBSD 14.0-RELEASE-p11