int modbus_receive_from(modbus_t *ctx, int sockfd, uint8_t *req);
The modbus_receive_from() function shall receive an indication request from the socket/file descriptor given in argument 'sockfd. This function is used by Modbus slave/server to receive and analyze indication request sent by the masters/clients.
The modbus_receive_from() function shall store the indication request in req and return the request length if sucessful. Otherwise it shall return -1 and set errno.
The libmodbus documentation was written by Stéphane Raimbault <m[blue][email protected]m>