Timer Class Reference
[Time measuring and Counting]

---

Detailed Description

Class for measuring the cpu time and real time usage of the process. It is quite easy-to-use, here is a short example.

      #include<lemon/time_measure.h>
      #include<iostream>
     
      int main()
      {
     
        ...
     
        Timer t;
        doSomething();
        std::cout << t << '\n';
        t.restart();
        doSomethingElse();
        std::cout << t << '\n';
     
        ...
     
      }

The Timer can also be stopped and started again, so it is possible to compute collected running times.

Warning:

Depending on the operation system and its actual configuration the time counters have a certain (10ms on a typical Linux system) granularity. Therefore this tool is not appropriate to measure very short times. Also, if you start and stop the timer very frequently, it could lead to distorted results.

Note:

If you want to measure the running time of the execution of a certain function, consider the usage of TimeReport instead.

Todo:

This shouldn't be Unix (Linux) specific.

See also:

TimeReport

Author:

Alpar Juttner

#include <lemon/time_measure.h>

Inheritance diagram for Timer:

[legend]

List of all members.

Public Member Functions
	Timer (bool run=true)
	Constructor.
Control the state of the timer
Basically a Timer can be either running or stopped, but it provides a bit finer control on the execution. The Timer also counts the number of start() executions, and is stops only after the same amount (or more) stop()s. This can be useful e.g. to compute the running time of recursive functions.
void	reset ()
	Reset and stop the time counters.
void	start ()
	Start the time counters.
void	stop ()
	Stop the time counters.
void	halt ()
	Halt (i.e stop immediately) the time counters.
int	running ()
	Returns the running state of the timer.
void	restart ()
	Restart the time counters.
Query Functions for the ellapsed time
double	userTime () const
	Gives back the ellapsed user time of the process.
double	systemTime () const
	Gives back the ellapsed system time of the process.
double	cUserTime () const
	Gives back the ellapsed user time of the process' children.
double	cSystemTime () const
	Gives back the ellapsed user time of the process' children.
double	realTime () const
	Gives back the ellapsed real time.
	operator TimeStamp () const
	Computes the ellapsed time.

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Constructor & Destructor Documentation

Timer

(

bool

run = true

)

[inline]

Parameters:

run

indicates whether or not the timer starts immediately.

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Member Function Documentation

void reset

(

)

[inline]

This function resets and stops the time counters

See also:

restart()

void start

(

)

[inline]

This function starts the time counters.

If the timer is started more than ones, it will remain running until the same amount of stop() is called.

See also:

stop()

void stop

(

)

[inline]

This function stops the time counters. If start() was executed more than once, then the same number of stop() execution is necessary the really stop the timer.

See also:

halt()

start()

restart()

reset()

void halt

(

)

[inline]

This function stops immediately the time counters, i.e. t.stop() is a faster equivalent of the following.

         while(t.running()) t.stop()

See also:

stop()

restart()

reset()

int running

(

)

[inline]

This function returns the number of stop() exections that is necessary to really stop the timer. For example the timer is running if and only if the return value is true (i.e. greater than zero).

void restart

(

)

[inline]

This function is a shorthand for a reset() and a start() calls.

operator TimeStamp

(

)

const [inline]

This conversion computes the ellapsed time, therefore you can print the ellapsed time like this.

         Timer t;
         doSomething();
         std::cout << t << '\n';