diff --git a/Sniffs/CodeAnalysis/VariableAnalysisSniff.php b/Sniffs/CodeAnalysis/VariableAnalysisSniff.php
index e822ad3..61b2cd1 100644
--- a/Sniffs/CodeAnalysis/VariableAnalysisSniff.php
+++ b/Sniffs/CodeAnalysis/VariableAnalysisSniff.php
@@ -330,7 +330,7 @@ class Generic_Sniffs_CodeAnalysis_VariableAnalysisSniff implements PHP_CodeSniff
         'yaz_hits' => array(2),
         'yaz_scan_result' => array(2),
         'yaz_wait' => array(1),
-        );
+    );
 
     /**
      *  Allows an install to extend the list of known pass-by-reference functions
@@ -356,6 +356,12 @@ class Generic_Sniffs_CodeAnalysis_VariableAnalysisSniff implements PHP_CodeSniff
      */
     public $validUnusedVariableNames = null;
 
+    /**
+     *  A list of names of variables that you want to ignore from
+     *  undefined variable warnings
+     */
+    public $validUndefinedVariableNames = null;
+
     /**
      * Returns an array of tokens this test wants to listen for.
      *
@@ -373,6 +379,12 @@ public function register() {
             $this->validUnusedVariableNames =
                 preg_split('/\s+/', trim($this->validUnusedVariableNames));
         }
+
+        if (!empty($this->validUndefinedVariableNames)) {
+            $this->validUndefinedVariableNames =
+                preg_split('/\s+/', trim($this->validUndefinedVariableNames));
+        }
+
         return array(
             T_VARIABLE,
             T_DOUBLE_QUOTED_STRING,
@@ -429,7 +441,7 @@ function scopeKey($currScope) {
             $currScope = 'file';
         }
         return ($this->currentFile ? $this->currentFile->getFilename() : 'unknown file') .
-            ':' . $currScope;
+        ':' . $currScope;
     }
 
     //  Warning: this is an autovivifying get
@@ -487,8 +499,8 @@ function markVariableDeclaration($varName, $scopeType, $typeHint, $stackPtr, $cu
                         VariableInfo::$scopeTypeDescriptions[$varInfo->scopeType],
                         "\${$varName}",
                         VariableInfo::$scopeTypeDescriptions[$scopeType],
-                        )
-                    );
+                    )
+                );
             }
         }
         $varInfo->scopeType = $scopeType;
@@ -534,9 +546,11 @@ function markVariableReadAndWarnIfUndefined($phpcsFile, $varName, $stackPtr, $cu
 
         if ($this->isVariableUndefined($varName, $stackPtr, $currScope) === true) {
             // We haven't been defined by this point.
-            $phpcsFile->addWarning("Variable %s is undefined.", $stackPtr,
-                'UndefinedVariable',
-                array("\${$varName}"));
+            if (!$this->validUndefinedVariableNames || !in_array($varName, $this->validUndefinedVariableNames)) {
+                $phpcsFile->addWarning("Variable %s is undefined.", $stackPtr,
+                    'UndefinedVariable',
+                    array("\${$varName}"));
+            }
         }
         return true;
     }
@@ -746,7 +760,7 @@ protected function checkForFunctionPrototype(
             $openPtr - 1, null, true, null, true);
         if (($functionPtr !== false) &&
             (($tokens[$functionPtr]['code'] === T_FUNCTION) ||
-             ($tokens[$functionPtr]['code'] === T_CLOSURE))) {
+                ($tokens[$functionPtr]['code'] === T_CLOSURE))) {
             // TODO: typeHint
             $this->markVariableDeclaration($varName, 'param', null, $stackPtr, $functionPtr);
             // Are we pass-by-reference?
@@ -871,7 +885,7 @@ protected function checkForSuperGlobal(
             '_ENV',
             'argv',
             'argc',
-            ))) {
+        ))) {
             return true;
         }
 
@@ -1047,7 +1061,7 @@ protected function checkForStaticDeclaration(
                 T_DOUBLE_COLON,
                 T_START_HEREDOC, T_HEREDOC, T_END_HEREDOC,
                 T_START_NOWDOC, T_NOWDOC, T_END_NOWDOC,
-                ),
+            ),
             $stackPtr - 1, null, true, null, true);
         if (($staticPtr === false) || ($tokens[$staticPtr]['code'] !== T_STATIC)) {
             //if ($varName == 'static4') {
@@ -1477,8 +1491,8 @@ protected function processScopeClose(
                     array(
                         VariableInfo::$scopeTypeDescriptions[$varInfo->scopeType],
                         "\${$varInfo->name}",
-                        )
-                    );
+                    )
+                );
             }
             if (isset($varInfo->firstInitialized)) {
                 $phpcsFile->addWarning(
@@ -1488,8 +1502,8 @@ protected function processScopeClose(
                     array(
                         VariableInfo::$scopeTypeDescriptions[$varInfo->scopeType],
                         "\${$varInfo->name}",
-                        )
-                    );
+                    )
+                );
             }
         }
     }
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..536ef1b
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,9 @@
+{
+  "name": "ingatlancom/variable-analysis",
+  "description": "Provides PHP CodeSniffer sniffs to find unused and undefined variables.",
+  "require": {
+    "php": ">=5.3.0",
+    "squizlabs/php_codesniffer": ">=1.5.3"
+  },
+  "license": "BSD-2-Clause"
+}
diff --git a/ruleset.xml b/ruleset.xml
index efa66ce..86ccc15 100644
--- a/ruleset.xml
+++ b/ruleset.xml
@@ -58,6 +58,16 @@
     junk
     dummy
     "/>
+  <!--
+     Include the following property if you want to have a whitelist of variable names
+     that are defined in all php files and that you don't want to provoke an undefined
+     variable warning for.
+     Format is "variableName" without a leading $ with whitespace delimiting names.
+  -->
+   <property name="validUndefinedVariableNames" value="
+    junk
+    dummy
+    "/>
   </properties>
  </rule>