modbus_mapping_new(3) [debian man page]

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)

Check Out this Related Man Page

MODBUS_NEW_TCP(3)						 Libmodbus Manual						 MODBUS_NEW_TCP(3)

NAME

       modbus_new_tcp - create a libmodbus context for TCP/IPv4

SYNOPSIS

       modbus_t *modbus_new_tcp(const char *ip, int port);

DESCRIPTION

       The modbus_new_tcp() function shall allocate and initialize a modbus_t structure to communicate with a Modbus TCP/IPv4 server.

       The ip argument specifies the IP address of the server to which the client wants etablish a connection.

       The 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 administrator privileges.

RETURN VALUE

       The modbus_new_tcp() 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
	   An invalid IP address was given.

EXAMPLE

	   modbus_t *ctx;

	   ctx = modbus_new_tcp("127.0.0.1", 1502);
	   if (ctx == NULL) {
	       fprintf(stderr, "Unable to allocate libmodbus context
");
	       return -1;
	   }

	   if (modbus_connect(ctx) == -1) {
	       fprintf(stderr, "Connection failed: %s
", modbus_strerror(errno));
	       modbus_free(ctx);
	       return -1;
	   }

SEE ALSO

       modbus_new_rtu(3) modbus_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_NEW_TCP(3)

Linux and UNIX Man Pages

modbus_mapping_new(3) [debian man page]

Check Out this Related Man Page