diff --git a/src/ops.c b/src/ops.c
index ed291d0..44cd473 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -5819,14 +5819,14 @@
  * Prepare for reading viminfo registers when writing viminfo later.
  */
     void
-prepare_viminfo_registers()
+prepare_viminfo_registers(void)
 {
      y_read_regs = (yankreg_T *)alloc_clear(NUM_REGISTERS
 						    * (int)sizeof(yankreg_T));
 }
 
     void
-finish_viminfo_registers()
+finish_viminfo_registers(void)
 {
     int		i;
     int		j;