whole_func_string: function list(PID, options, callback) {
    if (typeof options === 'function') {
      callback = options;
      options = {};
    }
  
    if (typeof options !== 'object') {
      options = {};
    }
  
    PID = parseInt(PID, 10);
    if (isNaN(PID) || PID < -1) {
      callback(new TypeError('The pid provided is invalid'));
      return;
    }
  
    getAll(function(err, list) {
      if (err) {
        callback(err);
        return;
      }
  
      // If the user wants the whole list just return it
      if (PID === -1) {
        for (var i = 0; i < list.length; i++) {
          list[i] = options.advanced
            ? {ppid: list[i][0], pid: list[i][1]}
            : (list[i] = list[i][1]);
        }
  
        callback(null, list);
        return;
      }
  
      var root;
      for (var l = 0; l < list.length; l++) {
        if (list[l][1] === PID) {
          root = options.advanced ? {ppid: list[l][0], pid: PID} : PID;
          break;
        }
  
        if (list[l][0] === PID) {
          root = options.advanced ? {pid: PID} : PID; // Special pids like 0 on *nix
        }
      }
  
      if (!root) {
        callback(new Error('No maching pid found'));
        return;
      }
  
      // Build the adiacency Hash Map (pid -> [children of pid])
      var tree = {};
      while (list.length > 0) {
        var e = list.pop();
        if (tree[e[0]]) {
          tree[e[0]].push(e[1]);
        } else {
          tree[e[0]] = [e[1]];
        }
      }
  
      // Starting by the PID provided by the user, traverse the tree using the
      // adiacency Hash Map until the whole subtree is visited.
      // Each pid encountered while visiting is added to the pids array.
      var idx = 0;
      var pids = [root];
      while (idx < pids.length) {
        var curpid = options.advanced ? pids[idx++].pid : pids[idx++];
        if (!tree[curpid]) continue;
        var len = tree[curpid].length;
        for (var j = 0; j < len; j++) {
          pids.push(
            options.advanced
              ? {ppid: curpid, pid: tree[curpid][j]}
              : tree[curpid][j]
          );
        }
  
        delete tree[curpid];
      }
  
      if (!options.root) {
        pids.shift(); // Remove root
      }
  
      callback(null, pids);
    });
  }
func_code_string: function list(PID, options, callback) {
    if (typeof options === 'function') {
      callback = options;
      options = {};
    }
  
    if (typeof options !== 'object') {
      options = {};
    }
  
    PID = parseInt(PID, 10);
    if (isNaN(PID) || PID < -1) {
      callback(new TypeError('The pid provided is invalid'));
      return;
    }
  
    getAll(function(err, list) {
      if (err) {
        callback(err);
        return;
      }
  
      // If the user wants the whole list just return it
      if (PID === -1) {
        for (var i = 0; i < list.length; i++) {
          list[i] = options.advanced
            ? {ppid: list[i][0], pid: list[i][1]}
            : (list[i] = list[i][1]);
        }
  
        callback(null, list);
        return;
      }
  
      var root;
      for (var l = 0; l < list.length; l++) {
        if (list[l][1] === PID) {
          root = options.advanced ? {ppid: list[l][0], pid: PID} : PID;
          break;
        }
  
        if (list[l][0] === PID) {
          root = options.advanced ? {pid: PID} : PID; // Special pids like 0 on *nix
        }
      }
  
      if (!root) {
        callback(new Error('No maching pid found'));
        return;
      }
  
      // Build the adiacency Hash Map (pid -> [children of pid])
      var tree = {};
      while (list.length > 0) {
        var e = list.pop();
        if (tree[e[0]]) {
          tree[e[0]].push(e[1]);
        } else {
          tree[e[0]] = [e[1]];
        }
      }
  
      // Starting by the PID provided by the user, traverse the tree using the
      // adiacency Hash Map until the whole subtree is visited.
      // Each pid encountered while visiting is added to the pids array.
      var idx = 0;
      var pids = [root];
      while (idx < pids.length) {
        var curpid = options.advanced ? pids[idx++].pid : pids[idx++];
        if (!tree[curpid]) continue;
        var len = tree[curpid].length;
        for (var j = 0; j < len; j++) {
          pids.push(
            options.advanced
              ? {ppid: curpid, pid: tree[curpid][j]}
              : tree[curpid][j]
          );
        }
  
        delete tree[curpid];
      }
  
      if (!options.root) {
        pids.shift(); // Remove root
      }
  
      callback(null, pids);
    });
  }
func_documentation_string: Get the list of children and grandchildren pids of the given PID.
  @param  {Number|String} PID A PID. If -1 will return all the pids.
  @param  {Object} [options] Optional options object.
  @param  {Boolean} [options.root=false] Include the provided PID in the list.
  @param  {Boolean} [options.advanced=false] Returns a list of objects in the
  format {pid: X, ppid: Y}.
  @param  {Function} callback(err, list) Called when the list is ready.