diff --git a/src/language.c b/src/language.c
index 1959409..ec87c1a 100644
--- a/src/language.c
+++ b/src/language.c
@@ -223,16 +223,6 @@ static const tidyLocaleMapItem localeMappings[] = {
 };
 
 
-/**
- *  Provides the mapping for LibTidy users to map between an opaque key
- *  and an error message value. See `tidyErrorFilterKeys[]`, below.
- */
-typedef struct tidyErrorFilterKeyItem {
-    ctmbstr key;
-    int value;
-} tidyErrorFilterKeyItem;
-
-
 /**
  *  LibTidy users may want to use `TidyReportFilter3` to enable their own
  *  localization lookup features. Because Tidy's errors codes are enums the
@@ -906,3 +896,53 @@ ctmbstr getNextInstalledLanguage( TidyIterator* iter )
     *iter = (TidyIterator)( itemIndex <= TY_(tidyInstalledLanguageListSize)() ? itemIndex : (size_t)0 );
     return item;
 }
+
+
+/**
+ *  Determines the number of error codes used by Tidy.
+ */
+const uint TY_(tidyErrorCodeListSize)()
+{
+    static uint array_size = 0;
+    
+    if ( array_size == 0 )
+    {
+        while ( tidyErrorFilterKeysStruct[array_size].key ) {
+            array_size++;
+        }
+    }
+    
+    return array_size;
+}
+
+/**
+ *  Initializes the TidyIterator to point to the first item
+ *  in Tidy's list of error codes that can be return with
+ *  `TidyReportFilter3`.
+ *  Items can be retrieved with getNextErrorCode();
+ */
+TidyIterator getErrorCodeList()
+{
+    return (TidyIterator)(size_t)1;
+}
+
+/**
+ *  Returns the next error code.
+ */
+const tidyErrorFilterKeyItem *getNextErrorCode( TidyIterator* iter )
+{
+    const tidyErrorFilterKeyItem *item = NULL;
+    size_t itemIndex;
+    assert( iter != NULL );
+    
+    itemIndex = (size_t)*iter;
+    
+    if ( itemIndex > 0 && itemIndex <= TY_(tidyErrorCodeListSize)() )
+    {
+        item = &tidyErrorFilterKeysStruct[itemIndex - 1];
+        itemIndex++;
+    }
+    
+    *iter = (TidyIterator)( itemIndex <= TY_(tidyErrorCodeListSize)() ? itemIndex : (size_t)0 );
+    return item;
+}
diff --git a/src/language.h b/src/language.h
index 6212033..6e78582 100644
--- a/src/language.h
+++ b/src/language.h
@@ -66,6 +66,22 @@ typedef struct tidyLocaleMapItem {
 } tidyLocaleMapItem;
 
 
+/**
+ *  The function getNextErrorCode() returns pointers to this type; it gives
+ *  LibTidy implementors the ability to know what errors can be returned
+ *  via `TidyReportFilter3`.
+ *  Provides the mapping for LibTidy users to map between an opaque key
+ *  and an error message value. See `tidyErrorFilterKeys[]` in `language.c`.
+ *  The `key` string is guaranteed by the API (unless deleted entirely). The
+ *  `value` is suitable for use in looking up Tidy's strings, but its value
+ *  is not guaranteed between releases.
+ */
+typedef struct tidyErrorFilterKeyItem {
+    ctmbstr key;
+    int value;
+} tidyErrorFilterKeyItem;
+
+
 /**
  *  Defines all of the possible dictionary keys.
  *  The starting value is arbitrary but must prevent overlaps
@@ -296,6 +312,20 @@ TidyIterator getInstalledLanguageList();
 ctmbstr getNextInstalledLanguage( TidyIterator* iter );
 
 
+/**
+ *  Initializes the TidyIterator to point to the first item
+ *  in Tidy's list of error codes that can be return with
+ *  `TidyReportFilter3`.
+ *  Items can be retrieved with getNextErrorCode();
+ */
+TidyIterator getErrorCodeList();
+
+/**
+ *  Returns the next error code.
+ */
+const tidyErrorFilterKeyItem *getNextErrorCode( TidyIterator* iter );
+
+
 /** @} */
 
 #endif /* language_h */