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d2b288b Jan 15, 2014
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modbus_write_and_read_registers(3)
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NAME
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modbus_write_and_read_registers - write and read many registers in a single transaction
SYNOPSIS
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*int modbus_write_and_read_registers(modbus_t *'ctx', int 'write_addr', int 'write_nb', const uint16_t *'src', int 'read_addr', int 'read_nb', const uint16_t *'dest');*
DESCRIPTION
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The *modbus_write_and_read_registers()* function shall write the content of the
_write_nb_ holding registers from the array 'src' to the address _write_addr_ of
the remote device then shall read the content of the _read_nb_ holding registers
to the address _read_addr_ of the remote device. The result of reading is stored
in _dest_ array as word values (16 bits).
You must take care to allocate enough memory to store the results in _dest_
(at least _nb_ * sizeof(uint16_t)).
The function uses the Modbus function code 0x17 (write/read registers).
RETURN VALUE
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The function shall return the number of read registers if successful. Otherwise
it shall return -1 and set errno.
ERRORS
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*EMBMDATA*::
Too many registers requested, Too many registers to write
SEE ALSO
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linkmb:modbus_read_registers[3]
linkmb:modbus_write_register[3]
linkmb:modbus_write_registers[3]
AUTHORS
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The libmodbus documentation was written by Stéphane Raimbault
<stephane.raimbault@gmail.com>