Mysensors RFM69 gateway compilation error on 64-bit OS (RFM69_MAX_PACKET_LEN)

[Frantisek Repkovsky]

Just for tracking this issue that has already been discussed in the forum long time ago but is not fixed yet.

When trying to build RFM69 mysgw on 64-bit OS the following error occurs:

test@raspberrypi:~/MySensors $ make
g++ -MT build/examples_linux/mysgw.o -MMD -MP -march=armv8-a+crc -mtune=cortex-a53 -DMY_RADIO_RFM69 -DMY_RFM69_NEW_DRIVER -DMY_GATEWAY_LINUX -DMY_DEBUG -DLINUX_SPI_BCM -DLINUX_ARCH_RASPBERRYPI -DMY_RFM69_FREQUENCY=RFM69_868MHZ -DMY_IS_RFM69HW -DMY_PORT=5003  -Ofast -g -Wall -Wextra -std=c++11 -I. -I./core -I./hal/architecture/Linux/drivers/core -I./hal/architecture/Linux/drivers/BCM -c examples_linux/mysgw.cpp -o build/examples_linux/mysgw.o
In file included from ./MySensors.h:388,
                 from examples_linux/mysgw.cpp:82:
./hal/transport/RFM69/driver/new/RFM69_new.cpp: In function ‘void RFM69_interruptHandling()’:
./hal/transport/RFM69/driver/new/RFM69_new.cpp:282:62: error: no matching function for call to ‘min(long unsigned int, unsigned int)’
  282 |                                          RFM69_MAX_PACKET_LEN);
      |                                                              ^

Workaround for this problem on 64-bit OS is to change RFM69_MAX_PACKET_LEN definition in RFM69_new.h:

test@raspberrypi:~/MySensors $ diff ./hal/transport/RFM69/driver/new/RFM69_new.h.orig ./hal/transport/RFM69/driver/new/RFM69_new.h
130c130
< #define RFM69_MAX_PACKET_LEN             (0x40u)              //!< This is the maximum number of bytes that can be carried 
---
> #define RFM69_MAX_PACKET_LEN             (0x40ul)             //!< This is the maximum number of bytes that can be carried

and then compilation works fine.

But this fix/workaround cannot be simply committed like above in the sources because doing it this way solves the problem on 64-bit OS but causes failure on 32-bit OS. It has to be done some other way...

[Frantisek Repkovsky]

This fix works for me on 64-bit and 32-bit OS - I tested building it and also running gateway and it works fine. But I'm not cpp programmer so better it is reviewed...

diff --git a/hal/transport/RFM69/driver/new/RFM69_new.cpp b/hal/transport/RFM69/driver/new/RFM69_new.cpp
index ed1f48b4..5357b6f3 100644
--- a/hal/transport/RFM69/driver/new/RFM69_new.cpp
+++ b/hal/transport/RFM69/driver/new/RFM69_new.cpp
@@ -278,7 +278,8 @@ LOCAL void RFM69_interruptHandling(void)
                                     RFM69.currentPacket.header.packetLen - 1);
 
                        if (RFM69.currentPacket.header.version >= RFM69_MIN_PACKET_HEADER_VERSION) {
-                               RFM69.currentPacket.payloadLen = min(RFM69.currentPacket.header.packetLen - (RFM69_HEADER_LEN - 1),
+                               RFM69.currentPacket.payloadLen = min(static_cast<uint>
+                                                                    (RFM69.currentPacket.header.packetLen - (RFM69_HEADER_LEN - 1)),
                                                                     RFM69_MAX_PACKET_LEN);
                                RFM69.ackReceived = RFM69_getACKReceived(RFM69.currentPacket.header.controlFlags);
                                RFM69.dataReceived = !RFM69.ackReceived;