diff --git a/src/os_amiga.c b/src/os_amiga.c
index 1361030..1d440aa 100644
--- a/src/os_amiga.c
+++ b/src/os_amiga.c
@@ -1123,7 +1123,7 @@
 dos_packet(
     struct MsgPort *pid,    /* process identifier ... (handlers message port) */
     long	    action, /* packet type ... (what you want handler to do)   */
-		    arg)    /* single argument */
+    long	    arg)    /* single argument */
 {
 # ifdef FEAT_ARP
     struct MsgPort	    *replyport;