diff --git a/src/libCom/macLib/macLibREADME b/src/libCom/macLib/macLibREADME
index 95114d905..f3cda53c2 100644
--- a/src/libCom/macLib/macLibREADME
+++ b/src/libCom/macLib/macLibREADME
@@ -164,12 +164,12 @@ d) char *macEnvExpand( char *src );
    pointer to this null-terminated string. It returns NULL if the source
    string contains any undefined references.
 
-e) char *macDefExpand( char *src, char *macros );
+e) char *macDefExpand( char *src, MAC_HANDLE *macros );
 
    This operates in the same manner as macEnvExpand, but takes an 
-   additonal string argument that contains a set of macro definitions in 
-   the current macParseDefns format. These macros are appended to the set
-   of macros from environment variables. 
+   optional macro handle that can contain a set of macro definitions. 
+   These macros are appended to the set of macros from environment 
+   variables when expanding the string. 
 
 f) long macReportMacros( MAC_HANDLE *handle );