Compiling issues with arduino-esp32

[cydanil]

Hi Patrick,

Thank you for taking the time to develop and maintain this library, it's very useful to me. I'm using it with the Arduino framework and an esp32 (arduino-esp32 v. 3.0.1).

I see that in the latest release, 1.4.0, you've added support for some remaining BER types, including TYPE_IPADDRESS.

This kinda breaks compilation as the esp32 IPAddress constructor expects one of ip_addr_t*, char*, uint8_t*, or uint32_t, whereas SequenceBER::decode initializes an IPAddressBER with nullptr, resulting in the following error:

/home/cydanil/Arduino/libraries/SNMP/src/BER.cpp: In member function 'virtual const uint32_t SNMP::SequenceBER::decode(unsigned char*)':
/home/cydanil/Arduino/libraries/SNMP/src/BER.cpp:422:44: error: conversion from 'int' to 'IPAddress' is ambiguous
  422 |                     ber = new IPAddressBER(0);
      |                                            ^
In file included from /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/cores/esp32/Arduino.h:196,
                 from /home/cydanil/Arduino/libraries/SNMP/src/BER.h:4,
                 from /home/cydanil/Arduino/libraries/SNMP/src/BER.cpp:1:
/home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/cores/esp32/IPAddress.h:115:3: note: candidate: 'IPAddress::IPAddress(const ip_addr_t*)'
  115 |   IPAddress(const ip_addr_t *addr);
      |   ^~~~~~~~~
/home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/cores/esp32/IPAddress.h:72:3: note: candidate: 'IPAddress::IPAddress(const char*)'
   72 |   IPAddress(const char *address);
      |   ^~~~~~~~~
/home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/cores/esp32/IPAddress.h:69:3: note: candidate: 'IPAddress::IPAddress(const uint8_t*)'
   69 |   IPAddress(const uint8_t *address);
      |   ^~~~~~~~~
/home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/cores/esp32/IPAddress.h:67:3: note: candidate: 'IPAddress::IPAddress(uint32_t)'
   67 |   IPAddress(uint32_t address);
      |   ^~~~~~~~~
/home/cydanil/Arduino/libraries/SNMP/src/BER.h:435:28: note:   initializing argument 1 of 'SNMP::IPAddressBER::IPAddressBER(IPAddress)'
  435 |     IPAddressBER(IPAddress value);
      |                  ~~~~~~~~~~^~~~~

Used library Version Path
Ethernet     2.0.0   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/libraries/Ethernet
Networking   1.0.0   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/libraries/Network
SPI          2.0.0   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/libraries/SPI
WiFi         2.0.0   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/libraries/WiFi
WebServer    2.0.0   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/libraries/WebServer
FS           2.0.0   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1/libraries/FS
SNMP         1.4.0   /home/cydanil/Arduino/libraries/SNMP

Used platform Version Path
esp32:esp32   3.0.1   /home/cydanil/.arduino15/packages/esp32/hardware/esp32/3.0.1

An easy fix for me is to modify BER.cpp, line 422 with something like: ber = new IPAddressBER((uint32_t) 0);

I appreciate that this may not be the target platform, but I'm happy to contribute a solution if you give me some guidance :slightly_smiling_face:

Thanks,
Cyril

[patricklaf]

Hello Cyril, Thank you for reporting the issue. This problem appeared with ESP32 3.0.x cores, but this is non sense to pass a null pointer as an IPAddress object. Nevertheless, I prefer this solution:

ber = new IPAddressBER(IPAddress()); 

It compiles on all the platforms (AVR, ESP32 and STM32). Feel free to test it and if it works well for you, you can create a pull request if you want. Regards, Patrick

[cydanil]

I indeed noticed the issue following upgrades of the arduino-esp toolchain to 3+.

I tested that with both ESP32 and STM32 hardware on my test setup, and it works as expected.
I'll create an MR with the change.

Thanks for your time,
Cyril

[patricklaf]

PR #10 merged. I let you close this issue. Best regards, Patrick

[cydanil]

Sweet, thanks @patricklaf !