Send ping in EditGameEvent

An EditGameEvent can interrupt tinking of an engine, and the engine
might or might not send back a move as a result of that thinking.
To solve this, a "force" command sent to an engine playing white or
black will now be followed by a "ping". (If supported, of course.)

diff --git a/backend.c b/backend.c
index a3a81ef..233fb8d 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -14974,6 +14974,11 @@ EditGameEvent ()
       case MachinePlaysBlack:
       case BeginningOfGame:
        SendToProgram("force\n", &first);
+       if (first.usePing) { // [HGM] always send ping when we might interrupt machine thinking
+         char buf[MSG_SIZ];
+         snprintf(buf, MSG_SIZ, "ping %d\n", initPing = ++first.lastPing);
+         SendToProgram(buf, &first);
+       }
        SetUserThinkingEnables();
        break;
       case PlayFromGameFile: