uv_udp_start_recv callback with nread = 0

[txdv]

UDP packets can be sent with 0 content.
The content of the UDP packet is literally nothing, we are just sending the udp header.

Now look at the callback:

typedef void (*uv_udp_recv_cb)(uv_udp_t* handle, ssize_t nread,  const uv_buf_t* buf, const struct sockaddr* addr, unsigned flags);

In the case of an empty udp packets we have nread == 0 and addr != NULL

When the udp handle is closed it also issues a callback with nread == 0 and addr == NULL.

This is bad API design. Users of libuv will forget to check for addr. It is already a bug in nodejs. You can't currently receive empty udp packets.

I propose to drop the callback with 0 on socket closing. Maybe add another callback in the fields.

[saghul]

Thanks for the report Andrius, will investigate.

[txdv]

At least it should be documented...

[txdv]

#1350

here is the pull request for documentation

[saghul]

For completeness, it's like this by design. #1350 landed enhancing documentation, thanks!