diff --git a/src/os_riscos.c b/src/os_riscos.c
index a1cdab4..7c6758b 100644
--- a/src/os_riscos.c
+++ b/src/os_riscos.c
@@ -654,7 +654,7 @@
     if (buf == NULL)
 	return -1;
     sprintf((char *)buf, "which %s", name);
-    p = get_cmd_output(buf, SHELL_SILENT);
+    p = get_cmd_output(buf, NULL, SHELL_SILENT);
     vim_free(buf);
     if (p == NULL)
 	return -1;