GNU/Linux |
RedHat 6.2(Zoot) |
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clock(3) |
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clock − Determine processor time
#include <time.h>
clock_t clock(void);
The clock() function returns an approximation of processor time used by the program.
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.
ANSI C. POSIX requires that CLOCKS_PER_SEC equals 1000000 independent of the actual resolution.
The C standard allows for arbitrary values at the start of the program; take the difference between the value returned from a call to clock() at the start of the program and the end to get maximum portability.
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.
times(2)
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clock(3) | ![]() |