LatMRG::Chrono Class Reference

This class acts as an interface to the system clock to compute the CPU time used by parts of a program. More...

#include <latmrg/Chrono.h>

Public Types
enum	TimeFormat {   SEC, MIN, HOURS, DAYS,   HMS }
	Types of units in which the time on a Chrono can be read or printed: in seconds (SEC), minutes (MIN), hours (HOUR), days (DAYS), or in the HH:MM:SS.xx format, with hours, minutes, seconds and hundreths of a second (HMS). More...

Public Member Functions
	Chrono ()
	Constructor for a stopwatch; initializes it to zero. More...
	~Chrono ()
	Destructor. More...
void	init ()
	(Re)Initializes this stopwatch to zero. More...
bool	timeOver (double limit)
	Returns true if this Chrono has reached the time limit (in seconds), otherwise returns false. More...
std::string	toString ()
	Returns as a string the CPU time measured by this Chrono since its last call to init(). More...
double	val (TimeFormat unit)
	Returns the CPU time measured by this Chrono since the last call to init(). More...
void	write (TimeFormat unit)
	Prints, on standard output, the CPU time measured by this Chrono since its last call to init(). More...

Private Member Functions
void	tick ()
	Function returning the CPU time used by the program since it was started. More...

Private Attributes
unsigned long	microsec
	Microseconds. More...
unsigned long	second
	Seconds. More...

Detailed Description

This class acts as an interface to the system clock to compute the CPU time used by parts of a program.

Even though the ANSI/ISO macro CLOCKS_PER_SEC = 1000000 is the number of clock ticks per second for the value returned by the ANSI-C standard clock function (so this function returns the number of microseconds), on some systems where the 32-bit type long is used to measure time, the value returned by clock wraps around to negative values after about 36 minutes. On some other systems where time is measured using the 32-bit type unsigned long, the clock may wrap around to 0 after about 72 minutes. When the macro USE_ANSI_CLOCK is undefined, a non-ANSI-C clock is used. On Linux-Unix systems, it calls the POSIX function times to get the CPU time used by a program. On a Windows platform (when the macro HAVE_WINDOWS_H is defined), the Windows function GetProcessTimes will be used to measure the CPU time used by programs. On Linux \(|\)Unix platforms, if the macro USE_ANSI_CLOCK is defined, the timers will call the ANSI C clock function. When USE_ANSI_CLOCK is left undefined, class Chrono gets the CPU time used by a program via an alternate non-ANSI C timer based on the POSIX (The Portable Operating System Interface) function times, assuming this function is available. The POSIX standard is described in the IEEE Std 1003.1-2001 document (see The Open Group web site at http://www.opengroup.org/onlinepubs/007904975/toc.htm).

Every object Chrono acts as an independent stopwatch. Several such stopwatchs can run at any given time. An object of type Chrono must be declared for each of them. The method init resets the stopwatch to zero, val returns its current reading, and write writes this reading to the current output. The returned value includes part of the execution time of the functions from class Chrono. The TimeFormat allows one to choose the kind of time units that are used.

Below is an example of how the functions may be used. A stopwatch named timer is declared and created. After 2.1 seconds of CPU time have been consumed, the stopwatch is read and reset. Then, after an additional 330 seconds (or 5.5 minutes) of CPU time the stopwatch is read again, printed to the output and deleted.

Chrono timer;
(...) (suppose 2.1 CPU seconds are used here.)
double t = timer.val (Chrono::SEC); // Here, t = 2.1
timer.init();
(...) (suppose 330 CPU seconds are used here.)
t = timer.val (Chrono::MIN); // Here, t = 5.5
timer.write (Chrono::HMS); // Prints: 00:05:30.00

Member Enumeration Documentation

TimeFormat

enum LatMRG::Chrono::TimeFormat

Types of units in which the time on a Chrono can be read or printed: in seconds (SEC), minutes (MIN), hours (HOUR), days (DAYS), or in the HH:MM:SS.xx format, with hours, minutes, seconds and hundreths of a second (HMS).

Enumerator
SEC
MIN
HOURS
DAYS
HMS

Constructor & Destructor Documentation

Chrono()

LatMRG::Chrono::Chrono

(

)

Constructor for a stopwatch; initializes it to zero.

One may reinitialize it later by calling init.

~Chrono()

LatMRG::Chrono::~Chrono ( )

inline

Destructor.

Member Function Documentation

init()

void LatMRG::Chrono::init

(

)

(Re)Initializes this stopwatch to zero.

tick()

void LatMRG::Chrono::tick ( )

private

Function returning the CPU time used by the program since it was started.

This function depends on the operation system and is not intended to be manipulated directly.

timeOver()

bool LatMRG::Chrono::timeOver

(

double

limit

)

Returns true if this Chrono has reached the time limit (in seconds), otherwise returns false.

toString()

std::string LatMRG::Chrono::toString

(

)

Returns as a string the CPU time measured by this Chrono since its last call to init().

The time format used is HMS.

val()

double LatMRG::Chrono::val

(

TimeFormat

unit

)

Returns the CPU time measured by this Chrono since the last call to init().

The parameter unit specifies the time unit. Restriction: unit = HMS is not allowed here; it will cause an error.

write()

void LatMRG::Chrono::write

(

TimeFormat

unit

)

Prints, on standard output, the CPU time measured by this Chrono since its last call to init().

The parameter unit specifies the time unit.

Member Data Documentation

microsec

unsigned long LatMRG::Chrono::microsec

private

Microseconds.

second

unsigned long LatMRG::Chrono::second

private

Seconds.

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The documentation for this class was generated from the following files:

• include/latmrg/Chrono.h
• src/latmrg/Chrono.cc