Moved template functions to header to avoid linker errors

src/sinqController.h

@@ -380,9 +380,17 @@ class epicsShareClass sinqController : public asynMotorController {
      */
     int outstandingForcedFastPolls();
 
-    // Maximum error message buffer size. This is an empirical value which must
-    // be large enough to avoid overflows for all commands to the device /
-    // responses from it.
+    /**
+     * @brief Return the maximum error message buffer size
+     *
+     * This is an empirical value which must be large enough to avoid overflows
+     * for all commands to the device / responses from it.
+     *
+     * @return uint32_t
+     */
+    uint32_t msgSize() { return MAXBUF_; }
+
+    // Maximum message size
     static const uint32_t MAXBUF_ = 200;
 
     // =========================================================================