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
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
/* 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; }
AUTHORS
The libmodbus documentation was written by Stéphane Raimbault <stephane.raimbault@gmail.com>