diff --git a/ff_dir.c b/ff_dir.c
index 8ea3c5c..1a80edf 100644
--- a/ff_dir.c
+++ b/ff_dir.c
@@ -2884,9 +2884,9 @@ FF_Error_t FF_ExtendDirectory( FF_IOManager_t * pxIOManager,
 
 /* *INDENT-OFF* */
 #if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
-    BaseType_t FF_IsNameCompliant( FF_T_WCHAR * pcName )
+    BaseType_t FF_IsNameCompliant( const FF_T_WCHAR * pcName )
 #else
-    BaseType_t FF_IsNameCompliant( char * pcName )
+    BaseType_t FF_IsNameCompliant( const char * pcName )
 #endif
 /* *INDENT-ON* */
 {
diff --git a/include/ff_dir.h b/include/ff_dir.h
index 4a23624..71d5b55 100644
--- a/include/ff_dir.h
+++ b/include/ff_dir.h
@@ -177,9 +177,9 @@ int8_t FF_PushEntry( FF_IOManager_t * pxIOManager,
  * contains any legal characters only.
  */
 #if ( ffconfigUNICODE_UTF16_SUPPORT != 0 )
-    BaseType_t FF_IsNameCompliant( FF_T_WCHAR * pcName );
+    BaseType_t FF_IsNameCompliant( const FF_T_WCHAR * pcName );
 #else
-    BaseType_t FF_IsNameCompliant( char * pcName );
+    BaseType_t FF_IsNameCompliant( const char * pcName );
 #endif
 
 static portINLINE BaseType_t FF_isEndOfDir( const uint8_t * pucEntryBuffer )