2 files changed, 2 insertions, 2 deletions
diff --git a/src/output.c b/src/output.c
index bf9a4d7..56a78c2 100644
--- a/src/output.c
+++ b/src/output.c
@@ -52,7 +52,7 @@ void scan_gas(gas_t *gas, char *str)
     *gas = gas_new(o2, he, MOD_AUTO);
 }
 
-void print_planhead()
+void print_planhead(void)
 {
     wprintf(L"DIVE PLAN\n\n");
     wprintf(L" %-1s  %-5s  %-8s  %-7s  %1s %-9s  %-4s  %-3s\n", "", "Depth", "Duration", "Runtime", "", "Gas", "pO2",
diff --git a/src/output.h b/src/output.h
index 5cc3adc..017e319 100644
--- a/src/output.h
+++ b/src/output.h
@@ -13,7 +13,7 @@
 #define SWI 0x21BB /* Clockwise Open Circle Arrow */
 
 /* functions */
-void print_planhead();
+void print_planhead(void);
 void print_planline(const wchar_t sign, const double depth, const double time, const double runtime, const gas_t *gas);
 void print_planfoot(const decostate_t *ds);