43 lines
948 B
V
43 lines
948 B
V
import context
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// This example demonstrates the use of a cancelable context to prevent a
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// routine leak. By the end of the example function, the routine started
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// by gen will return without leaking.
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fn test_with_cancel() {
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// gen generates integers in a separate routine and
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// sends them to the returned channel.
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// The callers of gen need to cancel the context once
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// they are done consuming generated integers not to leak
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// the internal routine started by gen.
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gen := fn (ctx context.Context) chan int {
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dst := chan int{}
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go fn (ctx context.Context, dst chan int) {
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mut v := 0
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ch := ctx.done()
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for {
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select {
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_ := <-ch {
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// returning not to leak the routine
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return
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}
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dst <- v {
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v++
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}
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}
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}
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}(ctx, dst)
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return dst
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}
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ctx := context.with_cancel(context.background())
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defer {
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context.cancel(ctx)
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}
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ch := gen(ctx)
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for i in 0 .. 5 {
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v := <-ch
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assert i == v
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}
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}
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