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Hello, welcome back.

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In this lesson, we're going to see how to change the priority of a task during runtime, I'll make

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a copy of our last project, number four, top priority here.

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Copy and then paste over here.

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And then I'll call this number five.

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Change in priority in runtime, I'll call this.

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OK.

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So I'm going to open this and then.

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I'm going to open or may not see, right, so let's see in our task creation, we have Gnarl here and

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now here we made use of this Fastenal.

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We know this now.

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As for the the task parameter, if we have any task parameter, this where we pass it, this second

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null is for a variable to hold the task.

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Hondo, we've never used the task Hondo.

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However, in this lesson we're going to introduce the tasks the task handle the task undo allows us

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to configure the task during runtime.

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We need a handle of the task.

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You can think of something you hold in order to control something.

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So we need a handle of the task to be able to configure it or make changes to it.

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So I'm going to come over here.

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And then I'm going to I'm going to have the task Hondo here.

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Task Hondo, let's see, I'm going to see task, I'm going to create a task Hondo type.

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And then I call this blue Hondo for blue Tosk, red Honda for Red Tosk.

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And then we have green Honda.

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OK, so I'm going to pass these condos to the various tasks, so over here, when we created Blue Task,

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I'll copy this.

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The last document is supposed to be the position of the ampersand over here.

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And then there's the name of the variable essentially parsing the address here.

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So Red would have this.

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And then green controversy would have this.

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OK, so we have the task, hundreds now.

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Now we come to our task functions, we said we want to change the priority of the tasks.

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We're going to start off the C, we're going to start off by let's say we give Blue a priority of two

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rights during creation.

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Blue has a priority of two.

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Red has a priority of two as well.

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And then let's say Green has.

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Greenhaus, a priority of one, so we know what's going to happen, essentially based on our previous

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experiment, when we run the program, we're going to have just blue and red executing and green won't

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have any time at all to execute.

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OK, so what are we going to do is we know blue is going to be executed.

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We're going to go into the task function of blue and then we would use that to set the priority of green

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higher.

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So over here, when we start off, green has a priority of one.

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So we would go inside.

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We'll go inside one of the execution, was it a blue or red and then change the priority of green shirt

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that so I'll come over here to red.

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So red increment, it's variable and then let's say it delays for a while.

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It will delay for let's say, I'll say four over here.

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I'll put a local variable here and I say, for I equals zero,

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sorry about the composition in the microphone equals zero.

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I less than, let's say, a value such as seven hundred thousand.

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I plus plus there's a reason I'm not using delay functions, actually delay functions here because.

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When we get to where the task goes to sleep, we would use the delay, you use the delay to essentially

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put the task to sleep and by putting it to sleep, the scheduler removes it from running states.

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We don't want that.

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We just want we want to simulate delay.

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We don't want to put it to sleep.

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That is why we use in for loops here.

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You would understand when we get to the bit where we are, we put in the task to sleep, OK?

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So over here we delay for this amount and the function for the priority is the V task priority set function.

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And this function takes the argument.

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The first argument is the handle of the task, whose priority you wish to set.

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And the second argument is the new priority level you want to assign to that task.

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So come over here, I'll say.

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The task priority said.

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And then I want to said this to green task, so I use the green Honda and then I want to assign priority

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three to it like this.

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OK, so let's run this and see what we have.

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Click over here to build.

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OK, that's an issue, but as I say.

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The task.

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We top priority set.

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What does it say to function as a green Honda, Undeclared says?

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OK, I'm using a cocktail here, it should be a small H.

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Click here to build.

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OK, it's both successfully.

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Click here to get onto the board.

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Yes, well, we need number five here.

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OK.

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Click here to switch.

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OK, so let's see what's going to happen or what we expect to happen with created three tasks, the

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first task as priority of to the second highest priority of two.

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The third one is the green task, the highest priority of one.

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So when we start, we're going to have just these two tasks running.

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But inside a red task, we call a function to set the priority of green task to three.

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So all of a sudden the priority of green becomes the highest.

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So let's see what happens.

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Click to run.

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OK.

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So that is what we ended up with these two Froese.

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Essentially so red.

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OK, imposed this.

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So blue started blue and red, they started with the same priority level, so they were sharing the

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time blue was expected to execute for X amount of time, say ten milliseconds.

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After ten milliseconds, red would execute for ten milliseconds and then blue blue would execute again

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for ten milliseconds and then ready to execute again for ten milliseconds, then to continue going back

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and forth like that because they have equal priority and then the other one has a lower priority.

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But this will happened blue finish executing for the assigned amount of time or known as the time cancer.

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But when Red tried to consume all of it time, when Red started executing its first executing its first

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execution, the first line is to increment the variable and then wait for a bit.

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And then the second line is to execute this instruction, which essentially said to the priority of

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green to three.

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So when that happened, red was taken off the color red was taken from the time time was taken from

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red.

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So red was moved out of the running states.

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All of a sudden Green had the highest priority.

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So Green started executing and green is going to execute forever.

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So because now green house priority of three, the rest just have priority of two.

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So you see just green task executing.

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So we've essentially changed the priority of green during runtime, right?

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Very easy.

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Very straightforward.

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These are just the basics.

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It's important to to get familiar with the basics, every aspect of it, before you start building a

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full project out of them.

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So, yeah.

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So we've seen how a task can can change the priority of another task.

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What if a task wants to change its own priority?

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How about that?

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So what are we going to do known as?

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I'm going to comment this out.

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Well, I could have created a new project for this so that you have the two projects for revision,

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but it's such a tiny change, I think you would remember.

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So I comment this out.

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And.

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What I'm going to do is.

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I'm going to start off.

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You know what, you know what's just bear with me, I think for your revision, I've done this thing

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for four years.

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It's important for students to have these projects separate.

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I'm going to create a new project just to demonstrate that I'll save this as it was, and then I'm going

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to come over here.

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And then creates a new project.

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OK, so come over here.

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Copy and then paste this over here.

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Number six.

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And then change in own priorities.

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I call this.

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OK, so I'm going to open this.

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Right.

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So what are we going to do here is over here, I'm going to start off by keeping blue.

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Blue is going to be created with priority number two.

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The other one red who have priority one in green will have priority one.

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So when we start just blue be executed.

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But what are we going to do is we're going to let Blue drop down its priority when the program starts.

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I'm going to clean this from the previous projects.

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So I'm going to go to the the task function of blue and I'm going to say sets priority of blue to one.

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So blue is going to increment just one.

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Its profile would increment just once and then we're going to drop the priority of blue to one.

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And when the priority of blue drops to want everyone to have access to time, everyone would run for

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equal amount of time.

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Let's see.

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So to do this, we use the same priority V task.

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Priority said.

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The first argument is now, and the second argument is the priority level, so if you want to change

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the priority of the task from which you are calling this function, you pass null.

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So I can either personally hear or I can pause blue Honda, remember Blue House to I can see blue Honda,

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but because I'm in blue, I can simply say no.

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Okay, I'll click here to run.

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And then click here to do it on our click here to build and then this one to run, this number six.

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I say, OK, over here.

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Switch.

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So let's see.

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OK, so as you can see, they're all running, but we know how we started, it started with blue.

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It started with.

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It started with blue incrementing once and then setting the priority for the rest.

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Right.

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But it looks as if.

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These two red and green are running more than blue.

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The see?

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OK, so I suppose what happened is when the priority of blue dropped, the priority of blue became the

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the same priority as red and green, but blue went to the back of the queue, so red and green had to

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execute before blue had its chance to execute.

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So that is why I would see this disparity here.

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Right.

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Because it's counting.

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It's yeah, it's cumulative.

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But now they are all executed for equal amount of time because they have equal priority.

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Right.

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So this is a with changing TASC priorities will conclude the lesson here.

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If you have any questions at all, you should leave them in the questions and answers area and I'll

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see you later.

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Finding the course useful or if you have any feedback at all, do leave it in the in the review area.

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I'll see you have a nice to.