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Com-AugustCellars / CoAP-CSharp

CoAP Implementation in C#
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ReceiveMessageFromAsync NotImplementedException on Android #81

Closed trampster closed 4 years ago

trampster commented 4 years ago

4 months ago ReceiveFromAsync was changed to ReceiveMessageFromAsync, but on Xamarin.Android this throws a NotImplementedException.

Here is the commit that changed it: https://github.com/Com-AugustCellars/CoAP-CSharp/commit/451e5bba4d2941a457b0741cc70631d0722a4f0c

jimsch commented 4 years ago

Would it be correct to assume that you do not have multicast in this situation?

trampster commented 4 years ago

Yes

jimsch commented 4 years ago

Please check to see of pull request #82 solves your problem.

trampster commented 4 years ago

That solves our problem, not sure of the threading here, maybe UseReceiveMessageFrom should be volatile, given that it is changing in one direction only (true to false) its probably OK, if a thread gets a cached version of it then it would just get the exception and then set to false and then be OK from then on.

It would be a nice if there was a way to detect we are running on mono and avoid the exceptions all together but I can't see any .net standard API that would do this.

jimsch commented 4 years ago

The threading is not an issue here because it is serialized farther up the stack.

It is possible to check if it is running on mono, but I don't know if it would be a valid check. It may be that mono does support this API for other platforms than Android. I would expect that it might be in iOS as multicast is easier to have running on that platform.

trampster commented 4 years ago

It's missing in the mono socket implementation see https://github.com/mono/mono/issues/20197, I wouldn't expect it to work on any mono platform.

Here is the socket code https://github.com/mono/mono/blob/master/mcs/class/System/System.Net.Sockets/Socket.cs

This is the accepted way of checking for mono: https://github.com/dotnet/runtime/blob/a297222753da9ae62dfe3304e4924ff74693c77d/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs#L22

At least your way would start using the new API if mono ever did implement it.

jimsch commented 4 years ago

I have no problems with making it mono dependent, but for now I think I will leave it along. One of the things I would really like to do is to run the unit tests under mono using the netframework but I have never been able to figure out a good way to do this. Do you have any setups for doing so?

I also assume from this that the decision I was thinking about of dropping the net framework version from the distribution would not make you happy,

trampster commented 4 years ago

We use it from .net standard, so if you only target .net standard then that would be fine with us. We use the .net standard version from mono on Android and iOS.

However .net standard isn't evenly implemented, mono 'officially' supports some .net standard api's by throwing either NotImplementedException or PlatformNotSupportedException, and the only easy way to find out is by using your .net standard libraries on mono :(

jimsch commented 4 years ago

82 merged