55 lines
990 B
Markdown
55 lines
990 B
Markdown
# Run In Background
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Run part of a program while the rest of it is doing something else.
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```sig
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control.inBackground(() => {
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})
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```
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## ~hint
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For more information, read
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[The @boardname@ - a reactive system](/device/reactive).
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It is pretty advanced!
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## ~
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## Example
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This program shows how running in the background can say what is
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stored in a variable like `num`, while another part (``on button pressed``)
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changes what is stored there.
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```blocks
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let num = 0
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control.inBackground(() => {
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while (true) {
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basic.showNumber(num)
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basic.pause(100)
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}
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})
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input.onButtonPressed(Button.A, () => {
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num++;
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})
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```
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This program does the same thing, but in a more usual way,
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with a ``forever`` loop.
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```blocks
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let num = 0
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basic.forever(() => {
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basic.showNumber(num)
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})
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input.onButtonPressed(Button.A, () => {
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num++;
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})
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```
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## See also
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[while](/blocks/loops/while), [forever](/reference/basic/forever),
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[on button pressed](/reference/input/on-button-pressed)
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