flush stdout after each modbus receive/reply when --monitor is enabled

Author: NikolasK-source

src/Modbus_TCP_Client_poll.cpp

@@ -198,6 +198,8 @@ void Client_Poll::set_debug(bool debug) {
         const std::string error_msg = modbus_strerror(errno);
         throw std::runtime_error("failed to enable modbus debugging mode: " + error_msg);
     }
+
+    this->debug = debug;
 }
 
 struct timeout_t {
@@ -380,6 +382,7 @@ Client_Poll::run_t Client_Poll::run(int signal_fd, bool reconnect, int timeout)
 
                 uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH];
                 int     rc = modbus_receive(modbus, query);
+                if (debug) std::cout.flush();
 
                 if (rc > 0) {
                     const auto CLIENT_ID = query[6];
@@ -409,6 +412,7 @@ Client_Poll::run_t Client_Poll::run(int signal_fd, bool reconnect, int timeout)
 
                     int ret = modbus_reply(modbus, query, rc, mapping);
                     if (semaphore && semaphore->is_acquired()) semaphore->post();
+                    if (debug) std::cout.flush();
 
                     if (ret == -1) {
                         std::cerr << Print_Time::iso << " ERROR: modbus_reply failed: " << modbus_strerror(errno)

src/Modbus_TCP_Client_poll.hpp

@@ -28,6 +28,8 @@ class Client_Poll {
     const std::size_t          max_clients;
     std::vector<struct pollfd> poll_fds;
 
+    bool debug = false;  //!< modbus debugging enabled
+
     modbus_t *modbus;  //!< modbus object (see libmodbus library)
     modbus_mapping_t
             *mappings[MAX_CLIENT_IDS];  //!< modbus data objects (one per possible client id) (see libmodbus library)