diff --git a/libsrc/common/_printf.h b/libsrc/common/_printf.h
index 15910096c..038697478 100644
--- a/libsrc/common/_printf.h
+++ b/libsrc/common/_printf.h
@@ -34,7 +34,7 @@ struct outdesc {
 
 
 /* Internal formatting routine */
-int __fastcall__ _printf (struct outdesc* d, const char* format, va_list ap);
+void __fastcall__ _printf (struct outdesc* d, const char* format, va_list ap);