Test and fix x509_oid functions
diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index ad8049a..003154b 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -212,6 +212,8 @@
/**
* \brief Give an known OID, return its descriptive string.
+ * (Deprecated. Use oid_get_extended_key_usage() instead.)
+ * Warning: only works for extended_key_usage OIDs!
*
* \param oid buffer containing the oid
*
@@ -228,8 +230,8 @@
* \param size Maximum size of buffer
* \param oid Buffer containing the OID
*
- * \return The amount of data written to the buffer, or -1 in
- * case of an error.
+ * \return Length of the string written (exluding final NULL) or
+ * POLARSSL_ERR_OID_BUF_TO_SMALL in case of error
*/
int x509_oid_get_numeric_string( char *buf, size_t size, x509_buf *oid );