diff --git a/lib/readline-sync.js b/lib/readline-sync.js
index f5449e4..af0884e 100644
--- a/lib/readline-sync.js
+++ b/lib/readline-sync.js
@@ -27,8 +27,8 @@ var
     caseSensitive:  false,
     noTrim:         false,
     encoding:       'utf8',
-    bufSize:        1024,
-    print:          null
+    bufferSize:     1024,
+    print:          void 0
   },
   useExt = false,
 
@@ -43,7 +43,7 @@ var
   limit:          string (pattern)
   caseSensitive:  boolean
   noTrim:         boolean
-  encoding, bufSize, print
+  encoding, bufferSize, print
 */
 function _readlineSync(options) {
   var input = '', displaySave = (options.display += ''),
@@ -147,7 +147,7 @@ function _readlineSync(options) {
       input = tryExt();
       return;
     }
-    buffer = new Buffer((reqSize = options.keyIn ? 1 : options.bufSize));
+    buffer = new Buffer((reqSize = options.keyIn ? 1 : options.bufferSize));
 
     if (options.keyIn && options.limit) {
       limit = new RegExp('[^' + options.limit + ']',
@@ -421,7 +421,7 @@ function margeOptions() {
 /* jshint eqnull:false */
           break;
         // number
-        case 'bufSize':                     // *    *
+        case 'bufferSize':                  // *    *
           if (!isNaN(value = parseInt(value, 10)) && typeof value === 'number')
             { options[optionName] = value; }
           break;
@@ -434,7 +434,7 @@ function margeOptions() {
           break;
         // function
         case 'print':                       // *    *
-          options[optionName] = typeof value === 'function' ? value : null;
+          options[optionName] = typeof value === 'function' ? value : void 0;
           break;
         // other
         case 'prompt':                      //      *
@@ -497,9 +497,14 @@ exports.setDefault = function(options) {
   return margeOptions(true); // copy
 };
 
-// These APIs are now obsolete.
-exports.setPrint = function(value) { return exports.setDefault({print: value}).print; };
-exports.setPrompt = function(value) { return exports.setDefault({prompt: value}).prompt; };
-exports.setEncoding = function(value) { return exports.setDefault({encoding: value}).encoding; };
-exports.setMask = function(value) { return exports.setDefault({mask: value}).mask; };
-exports.setBufferSize = function(value) { return exports.setDefault({bufSize: value}).bufSize; };
+// ======== These APIs are now obsolete. ========
+function setOption(optionName, args) {
+  var options;
+  if (args.length) { options = {}; options[optionName] = args[0]; }
+  return exports.setDefault(options)[optionName];
+}
+exports.setPrint = function() { return setOption('print', arguments); };
+exports.setPrompt = function() { return setOption('prompt', arguments); };
+exports.setEncoding = function() { return setOption('encoding', arguments); };
+exports.setMask = function() { return setOption('mask', arguments); };
+exports.setBufferSize = function() { return setOption('bufferSize', arguments); };