Peter M. Groen / libmodbus

It converts float values depending on what order they come in.

This patch was modified from rm5248 [1]

[1] https://github.com/synexxus/libmodbus/commit/a511768e7fe7ec52d7bae1d9ae04e33f87a59627

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

This reverts commit 1d3c6401f8186b54453ba64606758a90b6ec3fca.

TravisCI reports:
../src/.libs/libmodbus.so: undefined reference to `__builtin_bswap16'

with gcc 4.6.3

Thanks to dreamflow for the issue.

Making all in src
  CC       modbus.lo
  CC       modbus-data.lo
modbus-data.c:51:5: attention : #warning "Fallback on C functions for bswap_16" [-Wcpp]
 #   warning "Fallback on C functions for bswap_16"
     ^
modbus-data.c:52:24: erreur: redefinition of ‘bswap_16’
 static inline uint16_t bswap_16(uint16_t x)

Linking failed in Visual Studio due to unresolved bswap_16().

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>

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

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

Avoid incompatibility with GPLv2 program. This change has been approved by
Tobias Doerffel, Florian octo Forster and Hannu Vuolasaho.

Reported by Tobias Doerffel.

Reported by Allan Cornet.

modbus_set_slave must be used to set the slave ID of the remote
device to talk in master mode and to set the internal slave ID in
slave mode.

If you talk to several devices, you need to call modbus_set_slave
each time the following requests must be sent to another device.

All private functions and constants are now prefixed by _.
The modbus protocol uses entry points to call specific functions.