SYNOPSIS
modbus_t *modbus_new_tcp_pi(const char *node, const char *service);
DESCRIPTION
The modbus_new_tcp_pi() function shall allocate and initialize a modbus_t structure to communicate with a Modbus TCP IPv4 or Ipv6 server.
The node argument specifies the host name or IP address of the host to connect to, eg. 192.168.0.5 , ::1 or server.com.
The service argument is the service name/port number to connect to. To use the default Modbus port use the string "502". On many Unix systems, it’s convenient to use a port number greater than or equal to 1024 because it’s not necessary to have administrator privileges.
RETURN VALUE
The modbus_new_tcp_pi() 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.
ERRORS
- EINVAL
-
The node string is empty or has been truncated. The service string is empty or has been truncated.
EXAMPLE
AUTHORS
The libmodbus documentation was written by Stéphane Raimbault <stephane.raimbault@gmail.com>