diff --git a/reactos/lib/crtdll/string/strupr.c b/reactos/lib/crtdll/string/strupr.c
index 0cd73b83204..4cb0af4d196 100644
--- a/reactos/lib/crtdll/string/strupr.c
+++ b/reactos/lib/crtdll/string/strupr.c
@@ -12,7 +12,7 @@
 #include <crtdll/string.h>
 #include <crtdll/ctype.h>
 
-char *strupr(char *x)
+char *_strupr(char *x)
 {
 	char  *y=x;