modbus_reply(3) [debian man page]

MODBUS_REPLY(3) 						 Libmodbus Manual						   MODBUS_REPLY(3)

NAME

       modbus_reply - send a reponse to the received request

SYNOPSIS

       *int modbus_reply(modbus_t *ctx, const uint8_t *req, int req_length, modbus_mapping_t *mb_mapping);

DESCRIPTION

       The modbus_reply() function shall send a response to received request. The request req given in argument is analyzed, a response is then
       built and sent by using the information of the modbus context ctx.

       If the request indicates to read or write a value the operation will done in the modbus mapping mb_mapping according to the type of the
       manipulated data.

       If an error occurs, an exception response will be sent.

       This function is designed for Modbus server.

RETURN VALUE

       The modbus_reply() function shall return the length of the response sent if successful. Otherwise it shall return -1 and set errno.

ERRORS

       EMBMDATA
	   Sending has failed

       See also the errors returned by the syscall used to send the response (eg. send or write).

SEE ALSO

       modbus_reply_exception(3) libmodbus(7)

AUTHORS

       The libmodbus documentation was written by Stephane Raimbault <stephane.raimbault@gmail.com[1]>

NOTES

	1. stephane.raimbault@gmail.com
	   mailto:stephane.raimbault@gmail.com

libmodbus 3.0.3 						    05/26/2012							   MODBUS_REPLY(3)

MODBUS_MAPPING_NEW(3)						 Libmodbus Manual					     MODBUS_MAPPING_NEW(3)

NAME

       modbus_mapping_new - allocate four arrays of bits and registers

SYNOPSIS

       modbus_mapping_t modbus_mapping_new(int nb_bits, int nb_input_bits, int nb_registers, int nb_input_registers);*

DESCRIPTION

       The modbus_mapping_new() function shall allocate four arrays to store bits, input bits, registers and inputs registers. The pointers are
       stored in modbus_mapping_t structure. All values of the arrays are initialized to zero.

       If it isn't necessary to allocate an array for a specific type of data, you can pass the zero value in argument, the associated pointer
       will be NULL.

       This function is convenient to handle requests in a Modbus server/slave.

RETURN VALUE

       The modbus_mapping_new() function shall return the new allocated structure if successful. Otherwise it shall return NULL and set errno.

ERRORS

       ENOMEM
	   Not enough memory

EXAMPLE

	   /* The fist value of each array is accessible from the 0 address. */
	   mb_mapping = modbus_mapping_new(BITS_ADDRESS + BITS_NB,
					   INPUT_BITS_ADDRESS + INPUT_BITS_NB,
					   REGISTERS_ADDRESS + REGISTERS_NB,
					   INPUT_REGISTERS_ADDRESS + INPUT_REGISTERS_NB);
	   if (mb_mapping == NULL) {
	       fprintf(stderr, "Failed to allocate the mapping: %s
",
		       modbus_strerror(errno));
	       modbus_free(ctx);
	       return -1;
	   }

SEE ALSO

       modbus_mapping_free(3)

AUTHORS

       The libmodbus documentation was written by Stephane Raimbault <stephane.raimbault@gmail.com[1]>

NOTES

	1. stephane.raimbault@gmail.com
	   mailto:stephane.raimbault@gmail.com

libmodbus 3.0.3 						    05/26/2012						     MODBUS_MAPPING_NEW(3)