clock

 

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 CLOCK(3)            Linux Programmer's Manual            CLOCK(3)
 
 
 
NAME
        clock - Determine processor time
 
SYNOPSIS
        #include <time.h>
 
        clock_t clock(void);
 
DESCRIPTION
        The clock() function returns an approximation of processor
        time used by the program.
 
RETURN VALUE
        The value returned is the  CPU  time  used  so  far  as  a
        clock_t;  to  get  the  number  of seconds used, divide by
        CLOCKS_PER_SEC.  If the processor time used is not  avail­
        able  or  its  value  cannot  be represented, the function
        returns the value (clock_t)-1.
 
 CONFORMING TO
        ANSI C.  POSIX requires that CLOCKS_PER_SEC equals 1000000
        independent of the actual resolution.
 
NOTES
        The C standard allows for arbitrary values at the start of
        the program; subtract the value returned from  a  call  to
        clock()  at the start of the program to get maximum porta­
        bility.
 
        Note that the time can wrap around.   On  a  32bit  system
        where  CLOCKS_PER_SEC  equals  1000000  this function will
        return the same value approximately every 72 minutes.
 
        The times() function call returns more information.
 
SEE ALSO
        getrusage(2), times(2)
 
 
 
 GNU                         1993-04-21                   CLOCK(3)

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