diff --git a/VAX/vax780_uba.c b/VAX/vax780_uba.c
index 16e2e910..cbbf0c74 100644
--- a/VAX/vax780_uba.c
+++ b/VAX/vax780_uba.c
@@ -214,7 +214,7 @@ t_stat (*iodispW[IOPAGESIZE >> 1])(int32 dat, int32 ad, int32 md);
 
 /* Unibus interrupt request to interrupt action map */
 
-int32 (*int_ack[IPL_HLVL][32])();                       /* int ack routines */
+int32 (*int_ack[IPL_HLVL][32])(void);                   /* int ack routines */
 
 /* Unibus interrupt request to vector map */
 
diff --git a/VAX/vax_io.c b/VAX/vax_io.c
index a52d93ea..d0646c3f 100644
--- a/VAX/vax_io.c
+++ b/VAX/vax_io.c
@@ -188,7 +188,7 @@ t_stat (*iodispW[IOPAGESIZE >> 1])(int32 dat, int32 ad, int32 md);
 
 /* Interrupt request to interrupt action map */
 
-int32 (*int_ack[IPL_HLVL][32])();                       /* int ack routines */
+int32 (*int_ack[IPL_HLVL][32])(void);                   /* int ack routines */
 
 /* Interrupt request to vector map */