diff --git a/uisimulator/x11/dir.h b/uisimulator/x11/dir.h
index 662ed17359..48696c23b8 100644
--- a/uisimulator/x11/dir.h
+++ b/uisimulator/x11/dir.h
@@ -29,7 +29,7 @@ typedef void DIR;
 
 typedef void * MYDIR;
 
-extern MYDIR *x11_opendir(char *name);
+extern MYDIR *x11_opendir(const char *name);
 extern struct x11_dirent* x11_readdir(MYDIR* dir);
 extern int x11_closedir(MYDIR *dir);
 extern int x11_mkdir(char *name, int mode);
diff --git a/uisimulator/x11/io.c b/uisimulator/x11/io.c
index faccc826a7..d4d2714026 100644
--- a/uisimulator/x11/io.c
+++ b/uisimulator/x11/io.c
@@ -47,7 +47,7 @@ struct mydir {
 
 typedef struct mydir MYDIR;
 
-MYDIR *x11_opendir(char *name)
+MYDIR *x11_opendir(const char *name)
 {
     char buffer[256]; /* sufficiently big */
     DIR *dir;