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933ed4d May 10, 2016
@stephane @mhei
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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.
This function is equivalent to a call of the
linkmb:modbus_mapping_new_start_address[3] function with all start addresses to
`0`.
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 function shall return the new allocated structure if successful. Otherwise
it shall return NULL and set errno.
ERRORS
------
*ENOMEM*::
Not enough memory
EXAMPLE
-------
[source,c]
-------------------
/* The first 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\n",
modbus_strerror(errno));
modbus_free(ctx);
return -1;
}
-------------------
SEE ALSO
--------
linkmb:modbus_mapping_free[3]
linkmb:modbus_mapping_new_start_address[3]
AUTHORS
-------
The libmodbus documentation was written by Stéphane Raimbault
<stephane.raimbault@gmail.com>