Peter M. Groen / libmodbus

Thank you @pboettch for initial proposal.

Useful functions when you are confronted with equipment which does
not respect the protocol, which behaves strangely or when you wish
to move away from the standard.

Thank you @mhei for the great initial version.

When compiling with gcc and option -Wconversion it fixes the
warning message

  warning: conversion from ‘X’ {aka ‘x’} to ‘Y’ {aka ‘y’} may change value

Signed-off-by: José Bollo <jose.bollo@iot.bzh>

In case resulting value should be negative it is incorrect to use '+' operator to construct it from pieces, because highest bytes will result in negative number after bitwise shift while others will stay positive. Replacing addition with '|' should solve the issue.

Since SPDX release 3.0 LGPL-2.1+ became LGPL-2.1-or-later. Hence
replace the deprecated identifiers.

Closes #461

Related to 52ab1bbea760ed8eaca184f7d875a2f52a116d0f.
The arguments have been changed (see documentation).

https://groups.google.com/d/msg/libmodbus/aXO8nBzW4Ew/uVGTDmvvBAAJ

This allows to place the coils/registers at any virtual
start address, not only at address 0. This can be useful e.g.
when the server has to fulfill a specification in which
registers are expected at predefined locations.

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

This replaces the lengthy license text headers with a short
and standardized license tag. See http://spdx.org for details.

This is useful e.g. for license compliance tools which scan
through files and generate a report of the licenses used
in a project.

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

Function modbus_receive_from has no implementation in the library and is not used anywhere.

Change API of function for libmodbus v3.2.0

- add byte timeout tests (TCP backend only)
- update and improve documentation
- long timeout values are now uint32_t so it changes the API
  to disable byte timeout

https://www.securecoding.cert.org/confluence/display/seccode/DCL37-C.+Do+not+declare+or+define+a+reserved+identifier
Not applied to libmodbus constants for now...

- update documentation
- 5 new tests
- updated NEWS file
- avoid include of time.h

The index variable shadowed a variable in the standard library causing
warnings. Renaming the 'index' variable to 'idx' resolves the issue.

It's strongly recommended to update your libmodbus library if you
use it in a slave/server application in a not trusted environment.

Debian package of libmodbus 3.0.4 already contains a patch to
mitigate the exploit but the patch isn't as strong than this one.

This regression comes from Visual Studio patches.

- change return argument from void to int
- update documentation

Thanks Tobias Doerffel.

Fix EXXX values defined in Microsoft C Runtime 10

Add macros in libmodbus.txt and:
- modbus_get_byte_from_bits.txt
- modbus_get_float.txt
- modbus_reply.txt
- modbus_reply_exception.txt
- modbus_set_bits_from_byte.txt
- modbus_set_bits_from_bytes.txt
- modbus_set_float.txt