chain.go

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build test_run
     6  
     7  // Pass numbers along a chain of threads.
     8  
     9  package main
    10  
    11  import (
    12  	"runtime"
    13  	"strconv"
    14  
    15  	"cgostdio/stdio"
    16  )
    17  
    18  const N = 10
    19  const R = 5
    20  
    21  func link(left chan<- int, right <-chan int) {
    22  	// Keep the links in dedicated operating system
    23  	// threads, so that this program tests coordination
    24  	// between pthreads and not just goroutines.
    25  	runtime.LockOSThread()
    26  	for {
    27  		v := <-right
    28  		stdio.Stdout.WriteString(strconv.Itoa(v) + "\n")
    29  		left <- 1 + v
    30  	}
    31  }
    32  
    33  func main() {
    34  	leftmost := make(chan int)
    35  	var left chan int
    36  	right := leftmost
    37  	for i := 0; i < N; i++ {
    38  		left, right = right, make(chan int)
    39  		go link(left, right)
    40  	}
    41  	for i := 0; i < R; i++ {
    42  		right <- 0
    43  		x := <-leftmost
    44  		stdio.Stdout.WriteString(strconv.Itoa(x) + "\n")
    45  	}
    46  }
    47
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