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 available 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 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 approx-
imately every 72 minutes.
On several other implementations, the value returned by clock() also includes the times of any children whose status has been collected via
wait() (or another wait-type call). Linux does not include the times of waited-for children in the value returned by clock(). The times()
function, which explicitly returns (separate) information about the caller and its children, may be preferable.
SEE ALSO getrusage(2), times(2)GNU 2002-06-14 CLOCK(3)
Check Out this Related Man Page
clock(3) Library Functions Manual clock(3)NAME
clock - Reports CPU time used
LIBRARY
Standard C Library (libc.so, libc.a)
SYNOPSIS
#include <time.h>
clock_t clock (void);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
clock(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
DESCRIPTION
The clock() function reports the amount of processor time used by the calling process and each of its terminated child processes for which
a wait function has been executed. When a child process does not wait for its children, its child-process times are not included in its
times.
RETURN VALUES
The clock() function returns the amount of processor time (in microseconds) used since the first call to clock(). To convert the time to
seconds, divide it by CLOCKS_PER_SEC (which is defined to be 1,000,000 in <time.h>). If the processor time used is not available or its
value cannot be represented, the clock() function returns (clock_t)-1.
RELATED INFORMATION
Functions: ctime(3), getrusage(2), times(3), wait(2)
Standards: standards(5) delim off
clock(3)
I thought a program's elapsed time, some program language call it real time, should be the time of a program from start to finish. And it should be equal or longer than CPU time. This is true for the most of the cases. However, I do see some of my programs CPU time is longer than Elapsed time. ... (1 Reply)
Hello,
I am using C on a Centos box with gcc as the compiler.
I want a function to do something, them make an http request to some server (most probably using curl but suggestions are welcome) and return right away without waiting for the server's answer on that request.
What should I use... (8 Replies)
We have a program source C and is required to indicate how many times each function is called from the C program. also print the line number where there is a call.
I've tried something like this:
#!/bin/sh
for i in $*;do
if !
then
echo $i is not a C file.
else echo $i... (0 Replies)