[SignalR-Client-Cpp] cannot start a connection on linux arm

[Wasenshi123]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I built the lib for linux-arm environment (raspberry pi)

And I try to POC a simple connection to my signalr server (ASP .NET core 3.1).

What I get is an error below:

munmap_chunk(): invalid pointer
Aborted

This is the code which is basically a copy of example code on the github :

#include <iostream>

#include <future>

#ifndef WINDOWS
#define NO_SIGNALRCLIENT_EXPORTS
#endif // WINDOWS

#include "signalrclient/hub_connection.h"
#include "signalrclient/hub_connection_builder.h"
#include "signalrclient/signalr_value.h"


using namespace std;

int main(int argc, char **argv)
{
  std::promise<void> start_task;
  signalr::hub_connection connection = signalr::hub_connection_builder::create("http://192.168.0.21:8200/box").build();

  connection.on("NameChanged", [](const std::vector<signalr::value>& m)
  {
      std::cout << m[0].as_string() << std::endl;
  });

  connection.start([&start_task](std::exception_ptr ex) {
    if (ex) {
      std::cout << "Cannot connect to server." << std::endl;
      return 0;
    }

    std::cout << "server connected!" << std::endl;

    start_task.set_value();
  });

  std::cout << "connecting..." << std::endl;

  start_task.get_future().get();

  std::cout << "server connected!" << std::endl;


  return 0;
}

• I have tried with javascript client lib to check my server setup, the javascript lib can connect to my server via browser normally
• The RPi (raspberry pi) architect is ARM-linux-gnueabihf (64 bit)

Expected Behavior

The lib should be able to run and connect to server without error.

Steps To Reproduce

No response

Exceptions (if any)

munmap_chunk(): invalid pointer
Aborted

.NET Version

No response

Anything else?

No response

[Wasenshi123]

turned out I was using a signalr build that use flag -DUSE_CPPRESTSDK=false when I compiled my code on building PC then run the code on RPi which has another signalr lib build with flag -DUSE_CPPRESTSDK=true (I use cross-compiling method)

but another problem arose when I correct this:
I cannot build/compile my code and get this error instead:

.../armv8-rpi3-linux-gnueabihf/sysroot/lib/arm-linux-gnueabihf/libcpprest.so.2.10: undefined reference to `std::__cxx11::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::basic_ostringstream()@GLIBCXX_3.4.26'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/WebsocketTest.dir/build.make:84: bin/WebsocketTest] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/WebsocketTest.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

libcpprest.so.2.10: undefined reference to `std::__cxx11::basic_ostringstream<char, std::char_traits, std::allocator >::basic_ostringstream()@GLIBCXX_3.4.26'

[Wasenshi123]

The solution is:

for my case, I need to manually build everything from source myself (cross-compiling)

• First: go to cpprest github and follow their guide how to build on linux : https://github.com/Microsoft/cpprestsdk/wiki/How-to-build-for-Linux
• Second: build Signalr-Client-Cpp with option -DUSE_CPPRESTSDK=true. Follow the guide, but can skip the submodule part : https://github.com/aspnet/SignalR-Client-Cpp#build-on-linux

the working lib file should look like this:

• libcpprest.so.2.10 [5,155 KB]
• libmicrosoft-signalr.so [1,651 KB]