init

examples/stream_input_and_output.v

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+import io.string_reader
+import rand
+import runcmd
+import time
+
+fn main() {
+	// Prepare the command.
+	mut cmd := runcmd.new('cat')
+
+	// Setup I/O redirection.
+	cmd.redirect_stdio = true
+
+	// Start a process.
+	// Note: File descriptors will only become available after the process has started!
+	pid := cmd.start()!
+	println('Child process started with pid ${pid}')
+
+	// Get child file descriptors.
+	mut child_stdin := cmd.stdin()!
+	mut child_stdout := cmd.stdout()!
+
+	// Prepare reader to store command output.
+	mut output := string_reader.StringReader.new(reader: child_stdout)
+
+	// Start stdout reading in a coroutine.
+	//
+	// The reader will be block until the descriptor contains data.
+	// Therefore, to avoid blocking the main thread, we start the reader
+	// in a coroutine.
+	go fn [mut output] () {
+		println('STDOUT reader started!')
+		// Read stdout line by line until EOF.
+		for {
+			line := output.read_line() or { break }
+			println('Recv: ${line}')
+		}
+	}()
+
+	// Start sending data to child in a loop.
+	limit := 5
+	for _ in 0 .. limit {
+		// Generate some data.
+		data := rand.string(10) + '\n'
+		print('Send: ${data}')
+
+		// Write data to child stdin file descriptor.
+		_ := child_stdin.write(data.bytes())!
+
+		// Sleep a bit for demonstration.
+		time.sleep(500 * time.millisecond)
+	}
+
+	// Close stdin by hand so that the child process receives EOF.
+	// Without this child will hang for waiting for input.
+	child_stdin.close()!
+
+	// wait() will close the child stdout file desciptor by itself.
+	cmd.wait()!
+}