modbus_mapping_new(3)

1MODBUS_MAPPING_NEW(3)          libmodbus Manual          MODBUS_MAPPING_NEW(3)
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NAME

6       modbus_mapping_new - allocate four arrays of bits and registers
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SYNOPSIS

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

13       The modbus_mapping_new() function shall allocate four arrays to store
14       bits, input bits, registers and inputs registers. The pointers are
15       stored in modbus_mapping_t structure. All values of the arrays are
16       initialized to zero.
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18       This function is equivalent to a call of the
19       modbus_mapping_new_start_address(3) function with all start addresses
20       to 0.
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22       If it isn’t necessary to allocate an array for a specific type of data,
23       you can pass the zero value in argument, the associated pointer will be
24       NULL.
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26       This function is convenient to handle requests in a Modbus
27       server/slave.
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RETURN VALUE

30       The function shall return the new allocated structure if successful.
31       Otherwise it shall return NULL and set errno.
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ERRORS

34       ENOMEM
35           Not enough memory
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EXAMPLE

38           /* The first value of each array is accessible from the 0 address. */
39           mb_mapping = modbus_mapping_new(BITS_ADDRESS + BITS_NB,
40                                           INPUT_BITS_ADDRESS + INPUT_BITS_NB,
41                                           REGISTERS_ADDRESS + REGISTERS_NB,
42                                           INPUT_REGISTERS_ADDRESS + INPUT_REGISTERS_NB);
43           if (mb_mapping == NULL) {
44               fprintf(stderr, "Failed to allocate the mapping: %s\n",
45                       modbus_strerror(errno));
46               modbus_free(ctx);
47               return -1;
48           }
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AUTHORS

54       The libmodbus documentation was written by Stéphane Raimbault
55       <stephane.raimbault@gmail.com>
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59libmodbus v3.1.6                  02/04/2022             MODBUS_MAPPING_NEW(3)