From 5bbfa05ead1bff1e4a378ee6b24a7a2f5096738a Mon Sep 17 00:00:00 2001
From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Tue, 7 Apr 2020 12:11:33 +0200
Subject: [PATCH] Facilitate swapping clock messages

The routine SetClockMessage() now copies the message of the other clock
when it gets passed an empty string. To erase a message, we must pass
a NULL argument.
---
 dialogs.c           |    2 +-
 winboard/winboard.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/dialogs.c b/dialogs.c
index 4fa93c3..7c90898 100644
--- a/dialogs.c
+++ b/dialogs.c
@@ -3053,7 +3053,7 @@ DisplayBlackClock (long timeRemaining, int highlight)
 void
 SetClockMessage (int n, char *msg)
 {
-    safeStrCpy(clockMsg[n], msg, MSG_SIZ);
+    safeStrCpy(clockMsg[n], !msg ? "" : *msg ? msg : clockMsg[!n], MSG_SIZ);
 }
 
 //---------------------------------------------
diff --git a/winboard/winboard.c b/winboard/winboard.c
index 58508d6..10f66ea 100644
--- a/winboard/winboard.c
+++ b/winboard/winboard.c
@@ -9134,7 +9134,7 @@ DisplayBlackClock(long timeRemaining, int highlight)
 void
 SetClockMessage (int color, char *msg)
 {
-  safeStrCpy(clockMsg[n], msg, MSG_SIZ);
+  safeStrCpy(clockMsg[n], !msg ? "" : *msg ? msg : clockMsg[!n], MSG_SIZ);
 }
 
 int
-- 
1.7.0.4