SDL::Time

Section: User Contributed Perl Documentation (3)
Updated: 2019-07-26
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NAME

SDL::Time - An SDL Perl extension for managing timers  

CATEGORY

Core  

SYNOPSIS

 use warnings;
 use strict;
 
 use threads;
 use threads::shared;

 use SDL::Time;

 package foo;

 use SDL ':all';

 SDL::init(SDL_INIT_TIMER);

 my $tick :shared = 0;
 sub ticker { $tick++; warn $tick; return 100; }

 package main;

 my $id = SDL::Time::add_timer(100, 'foo::ticker');

 sleep(2);

 SDL::Time::remove_timer($id);

 

METHODS

 

add_timer

 my $id = SDL::Timer::add_timer( $ms_interval, $callback );

This runs in a separate thread and a cloned Perl thread. "threads" and "threads::shared" must be used to share any variables the timer uses.

The $callback function, specified with a string of the function's name, will be called after the milliseconds of $interval have elapsed. The actual delay may be longer than specified depending on the underlying OS. The callback function is passed the current timer interval as well as the $interval parameter and should return the next timer interval. If the return value from the callback is 0, the timer is cancelled; otherwise, the timer will continue to run.

The timer callback function may run in a different thread to your main program, so it shouldn't call any functions from within itself. You may call SDL::push_event, however.

"SDL::Time::add_timer" returns the identifier value of the generated timer or undef on error.

Note: You must initialize ("SDL::init") the timer subsystem to use this function.  

remove_timer

 SDL::Timer::remove_timer( $id );

The other way to cancel a timer is to use "SDL::Time::remove_timer" on the $id of a timer. This ID is the return value of the "SDL::Time::add_timer" function.

"SDL::Time::remove_timer" returns 0 on success or "-1" on error.  

AUTHORS

See ``AUTHORS'' in SDL.


 

Index

NAME
CATEGORY
SYNOPSIS
METHODS
add_timer
remove_timer
AUTHORS
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