diff --git a/src/db/callback.c b/src/db/callback.c
index 4e364b181..c387d79bb 100644
--- a/src/db/callback.c
+++ b/src/db/callback.c
@@ -60,6 +60,10 @@ static void *exitCallback;
 static char *threadName[NUM_CALLBACK_PRIORITIES] = {
     "cbLow", "cbMedium", "cbHigh"
 };
+#define FULL_MSG(name) "callbackRequest: " name " ring buffer full\n"
+static char *fullMessage[NUM_CALLBACK_PRIORITIES] = {
+    FULL_MSG("cbLow"), FULL_MSG("cbMedium"), FULL_MSG("cbHigh")
+};
 static unsigned int threadPriority[NUM_CALLBACK_PRIORITIES] = {
     epicsThreadPriorityScanLow - 1,
     epicsThreadPriorityScanLow + 4,
@@ -168,11 +172,7 @@ void callbackRequest(CALLBACK *pcallback)
     epicsInterruptUnlock(lockKey);
 
     if (!pushOK) {
-        char msg[48] = "callbackRequest: ";
-
-        strcat(msg, threadName[priority]);
-        strcat(msg, " ring buffer full\n");
-        epicsInterruptContextMessage(msg);
+        epicsInterruptContextMessage(fullMessage[priority]);
         ringOverflow[priority] = TRUE;
     }
     epicsEventSignal(callbackSem[priority]);