How to avoid using up cpu power?

SDL Development
1

Hi,
here is an urgent question.
How to avoid the program occupying all the cpu computing power
when waiting for events? I used SDL_WaitEvent.but seemed that no difference
with do{SDL_pollEvent())while(true);

wish getting your help as soon as possible . GREAT Thanks in advance.

yours roanldz.
4/23.

2

with do{SDL_pollEvent())while(true);

SDL_Event event;

while (1)
{
	SDL_PollEvent(&event);
	SDL_Delay(1);
}

…that will do it. The SDL_Delay(1) will pause until the first time it
can get control back after sleeping for x milliseconds, so specifying 1
millisecond will wait for at least one timeslice, which, while much more
than one millisecond, will suit your needs.

–ryan.

3

There is a SDL_WaitEvent which might be more efficient than this.On Sun, 22 Apr 2001, Ryan C. Gordon wrote:

with do{SDL_pollEvent())while(true);

SDL_Event event;

while (1)
{
SDL_PollEvent(&event);
SDL_Delay(1);
}

…that will do it. The SDL_Delay(1) will pause until the first time it
can get control back after sleeping for x milliseconds, so specifying 1
millisecond will wait for at least one timeslice, which, while much more
than one millisecond, will suit your needs.

4

Hi,
here is an urgent question.
How to avoid the program occupying all the cpu computing power
when waiting for events? I used SDL_WaitEvent.but seemed that no difference
with do{SDL_pollEvent())while(true);

In either case, your loop is probably running quite tightly. In the case of
the blocking function (WaitEvent, right? - it’s been a while ;^) ),
it’s probably not blocking for very long… it’s probably getting constant
mouse motion events. :wink:

When in doubt, stick an SDL_Delay() in to slow the loop down - it reduces
CPU usage.

-bill!

5

Heh, take a look at the source sometime.On Sun, Apr 22, 2001 at 03:14:37PM -0700, Lawrence W. Leung wrote:

There is a SDL_WaitEvent which might be more efficient than this.

On Sun, 22 Apr 2001, Ryan C. Gordon wrote:

with do{SDL_pollEvent())while(true);

SDL_Event event;

while (1)
{
SDL_PollEvent(&event);
SDL_Delay(1);
}

–
Martin

Bother! said Pooh, and twitted Roger Barnes.