CGAL::Timer Class Reference

#include <CGAL/Timer.h>

Definition

The class Timer is a timer class for measuring user process time.

Warning

When used to profile a multithreaded algorithm, this timer will add up the process time of each thread, which may be unexpected. To compute the wall-clock time of an algorithm, please consider using CGAL::Real_timer.

A timer t of type Timer is an object with a state. It is either running or it is stopped. The state is controlled with Timer::start() and Timer::stop(). The timer counts the time elapsed since its creation or last reset. It counts only the time where it is in the running state. The time information is given in seconds. The timer counts also the number of intervals it was running, i.e. it counts the number of calls of the Timer::start() member function since the last reset. If the reset occurs while the timer is running it counts as the first interval.

Implementation

The timer class is based on the C function std::clock() on PC systems and the C function getrusage() on standard POSIX systems. The counter for the std::clock() based solution might wrap around (overflow) after only about 36 minutes. This won't happen on POSIX systems. The system calls to these timers might fail, in which case a warning message will be issued through the CGAL error handler and the functions return with the error codes indicated above. The Timer::precision() method computes the precision dynamically at runtime at its first invocation.

Creation
	Timer ()
	state is stopped.

Operations
void	start ()
void	stop ()
void	reset ()
	reset timer to zero.
bool	is_running () const
	true if the current state is running.
double	time () const
	user process time in seconds, or 0 if the underlying system call failed.
int	intervals () const
	number of start/stop-intervals since the last reset.
double	precision () const
	smallest possible time step in seconds, or -1 if the system call failed.
double	max () const
	maximal representable time in seconds.

Member Function Documentation

reset()

void CGAL::Timer::reset

(

)

reset timer to zero.

The state is unaffected.

start()

void CGAL::Timer::start

(

)

Precondition

state is stopped.

stop()

void CGAL::Timer::stop

(

)

Precondition

state is running.