modbus_new_tcp - create a libmodbus context for TCP/IPv4
The modbus_new_tcp() function shall allocate and initialize a modbus_t structure to communicate with a Modbus TCP IPv4 server.
ip argument specifies the IP address of the server to which the client
wants to establish a connection. A NULL value can be used to listen any addresses in
port argument is the TCP port to use. Set the port to
MODBUS_TCP_DEFAULT_PORT to use the default one (502). It’s convenient to use a
port number greater than or equal to 1024 because it’s not necessary to have
The function shall return a pointer to a modbus_t structure if successful. Otherwise it shall return NULL and set errno to one of the values defined below.
- EINVAL, an invalid IP address was given.
- ENOMEM, out of memory. Possibly, the application hits its memory limit and/or whole system is running out of memory.