diff --git a/Cantera/src/converters/ck2ctml.cpp b/Cantera/src/converters/ck2ctml.cpp
index 072a8a97f..b9335c30f 100755
--- a/Cantera/src/converters/ck2ctml.cpp
+++ b/Cantera/src/converters/ck2ctml.cpp
@@ -564,8 +564,8 @@ namespace ctml {
     }
 
 
-    int convert_ck(const char* in_file, const char* db_file,
-        const char* tr_file, const char* out_file, const char* id_tag) {
+    int convert_ck(const char * const in_file, const char * const db_file,
+        const char * const tr_file, const char * const out_file, const char* const id_tag) {
         ckr::CKReader r;
         r.validate = true;
         //int i=1;
diff --git a/Cantera/src/converters/ck2ctml.h b/Cantera/src/converters/ck2ctml.h
index 86668b1f0..53ac59777 100755
--- a/Cantera/src/converters/ck2ctml.h
+++ b/Cantera/src/converters/ck2ctml.h
@@ -48,8 +48,8 @@ namespace ctml {
     void ck2ctml(string idtag, ckr::CKReader& r,
         XML_Node& root);
 
-    int convert_ck(const char* in_file, const char* db_file,
-        const char* tr_file, const char* out_file, const char* id_tag);
+    int convert_ck(const char * const in_file, const char * const db_file,
+        const char * const tr_file, const char * const out_file, const char * const id_tag);
 
 }