diff --git a/src/option.c b/src/option.c
index 4e087a5..8c72da6 100644
--- a/src/option.c
+++ b/src/option.c
@@ -8861,7 +8861,7 @@
 }
 #endif
 
-#if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3)
+#if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3) || defined(PROTO)
 /*
  * Returns the option attributes and its value. Unlike the above function it
  * will return either global value or local value of the option depending on
@@ -8874,7 +8874,8 @@
  * opt_type). Uses
  *
  * Returned flags:
- *       0 hidden or unknown option
+ *       0 hidden or unknown option, also option that does not have requested 
+ *         type (see SREQ_* in vim.h)
  *  see SOPT_* in vim.h for other flags
  *
  * Possible opt_type values: see SREQ_* in vim.h
@@ -8997,6 +8998,68 @@
 
     return r;
 }
+
+/*
+ * Iterate over options. First argument is a pointer to a pointer to a structure 
+ * inside options[] array, second is option type like in the above function.
+ *
+ * If first argument points to NULL it is assumed that iteration just started 
+ * and caller needs the very first value.
+ * If first argument points to the end marker function returns NULL and sets 
+ * first argument to NULL.
+ *
+ * Returns full option name for current option on each call.
+ */
+    char_u *
+option_iter_next(option, opt_type)
+    void	**option;
+    int		opt_type;
+{
+    struct vimoption	*ret = NULL;
+    do
+    {
+	if (*option == NULL)
+	    *option = (void *) options;
+	else if (((struct vimoption *) (*option))->fullname == NULL)
+	{
+	    *option = NULL;
+	    return NULL;
+	}
+	else
+	    *option = (void *) (((struct vimoption *) (*option)) + 1);
+
+	ret = ((struct vimoption *) (*option));
+
+	/* Hidden option */
+	if (ret->var == NULL)
+	{
+	    ret = NULL;
+	    continue;
+	}
+
+	switch (opt_type)
+	{
+	    case SREQ_GLOBAL:
+		if (!(ret->indir == PV_NONE || ret->indir & PV_BOTH))
+		    ret = NULL;
+		break;
+	    case SREQ_BUF:
+		if (!(ret->indir & PV_BUF))
+		    ret = NULL;
+		break;
+	    case SREQ_WIN:
+		if (!(ret->indir & PV_WIN))
+		    ret = NULL;
+		break;
+	    default:
+		EMSG2(_(e_intern2), "option_iter_next()");
+		return NULL;
+	}
+    }
+    while (ret == NULL);
+
+    return (char_u *)ret->fullname;
+}
 #endif
 
 /*