Node spawn stdout undefined

Question

I have this code:

Printer.prototype.watch = function() {   
  var self = this;   var args = ["-P", this.name];
  var lpq = spawn('lpq', args);

  lpq.stdout.on("data", function(data) {
    (some irrelevant code)   
  });

  lpq.on("exit", function() {
    self.watch();   
  }); 
};

After some recursive calls, spawn('lpq', args) returns a object with stdout=undefined. Why is this happening?

Answer 1

Try stderr so you can see the error message.

lpq.stderr.on("data", function(data) {
    console.log("stderr------",data.toString());
  });