Request: Return errno from native send()

[poppfd]

The RawChannel.send() method returns -1 if the send cannot be completed. Could the method somehow return an object including the errno set by the socket.h -> send() method? Or better yet, return the string parsed by strerror() to translate the errno to the system specific error.

I understand returning an object is less clear than number of bytes or -1. I'm hoping you might have an idea for how to cleanly provide this info.

I was debugging a CAN interface issue and found the send() returned -1. But I didn't realize I had a txqueuelen issue until I recompiled the socketcan C code to provide this errno context (105 ENOBUFS No buffer space available). It'd be nice if node-can could provide that error information.

[sebi2k1]

We would have to introduce a new set of function otherwise we would break compatibility with existing code. Did you tried reading ERRNO directly from the script? The send-call itself is synchronous and this should be the only syscall in the call chain (except if nodejs is doing some hidden syscall).

[poppfd]

Yea I understand backwards compatibility is a concern. I'm not super familiar with natively compiled C libraries for node so I thought you might have a more elegant solution. Not sure what you mean by "the script". If you mean the node script, I did not think the C errno variable was available in that scope. If I could get access to the errno variable, it looks like node will parse it with util.getSystemErrorName(errno) Like I said, I recompiled the can.cc file to return the errno string instead of number of bytes sent. I found this to be a crude, but workable solution.

[sebi2k1]

We can add an additional function to read the errno. Would that work?

[poppfd]

Yea I think that would work. So if we detect a failed send, we can read the errno and log from node.