I'd probably make the domain argument to uv_tcp_init_ex() a general purpose flags argument with the domain in the low bits.

There are only about 40-something address families and every platform I know of numbers them incrementally starting from zero, so you'd only need 6 bits to cover them all. Make it 8 or 10 bits to play it safe.

(Although that's wasting a lot of bits... AF_UNSPEC is always zero and AF_INET and AF_INET6 always < 32, AFAIK. But that aside.)

Can you elaborate a bit on why? Extensibility? FWIW, this is the first time that we modify some uv_*_init in years (if memory serves right), since they tend to basically do nothing, so I'm not really concerned about that.

Extensibility, yes. Always leave an escape hatch if at all possible.

Let's assume there is some UV_NO_CLOEXEC flag which prevents the sockets from being created with O_CLOEXEC set. This API would then be used as follows:

uv_tcp_init_ex(loop, handle, AF_INET|UV_NO_CLOEXEC);

Is that right? Looks a bit weird to me :-S I can add a dummy flags thing if you really feel strong about it:

int uv_tcp_init_ex(uv_loop_t*, uv_tcp_t* handle, int domain, int flags);
uv_tcp_init_ex(loop, handle, AF_INET, UV_NO_CLOEXEC|UV_DO_AWESOME_STUFF);

WDYT?

The three arg version looks alright to me and it's easier to remember, you can't accidentally swap the domain and the flags arguments. You can alias AF_INET as UV_AF_INET if using plain AF_INET bothers you.

@bnoordhuis is saghul@9e02f49 what you were suggesting?

@bnoordhuis I'm chasing some failures on Windows, but can you PTAL the unix side?

UNIX side LGTM minus some nits. Windows side looks okay to me too.

@bnoordhuis Thanks for the review! CI run here: https://jenkins-iojs.nodesource.com/view/libuv/job/libuv+any-pr+multi/109/

Ok, addressed everything and the build is "green" (surprisingly we've been keeping it that way on Windows for a while \o/).

If nobody has any further comments I'll land this and the LEP later tonight.

Thanks again for the review Ben!

Landed!

Just a followup, can you do an API bump in the master/v1.x so I can #ifdef for the new version?

@vavrusa we bump the version when making a release (the tool does it), so you'll have to wait until we make a 1.7.0 release, sorry.

Okay, a small request then - could you make a macro in uv-version.h (basically UV_VERSION from version.c) so I could check for version instead of MAJOR > 1 || MAJOR == 1 && (MINOR > 6 && ... in preprocessor? I like both decimal 171 or hex 0x00010700 ways.

Example:

#if UV_VERSION >= 0x00107000
#define ENABLE_REUSEPORT
#endif

Decimal is neater, but it requires you must use 1 digit per minor release at most.

@vavrusa sounds ok to me, here is a PR: #412

@vavrusa you can now use UV_VERSION_HEX.

BTW, the change to src/win/pipe.c in this change:

fb5df54

Is causing this problem:

luvit/luv#177

Removing this code from src/win/pipe.c:uv_set_pipe_handle() fixes the problem:

if (handle->handle != INVALID_HANDLE_VALUE)
return UV_EBUSY;

This error is triggered in this code path:

int uv_pipe_accept(uv_pipe_t* server, uv_stream_t* client) {
    ...
    if (server->ipc) {
        ...
    } else {
        ...
        if (!(server->flags & UV__HANDLE_CLOSING)) {
            uv_pipe_queue_accept(loop, server, req, FALSE);
        }
    }
}

static void uv_pipe_queue_accept(uv_loop_t* loop, uv_pipe_t* handle,
    uv_pipe_accept_t* req, BOOL firstInstance) {
    ...
    if (!firstInstance) {
        ...
        if (uv_set_pipe_handle(loop, handle, req->pipeHandle, -1, 0)) {
            ...
        }
    }
}

I could set server->handle = INVALID_HANDLE_VALUE; before uv_pipe_queue_accept() is called and fix this, but I don't know if that is the right thing to do.

I just had a nice chat with @saghul about this which probably triggered a lot of memories for him :-)
Here is what I ended up with to manually do the setsockopt call, might be useful for someone:

  uv_udp_t* socket = new uv_udp_t;
  uv_udp_init_ex(Loop::GetLoop(), socket, UV_UDP_RECVMMSG | AF_INET);

  uv_os_fd_t fd;
  if (uv_fileno(reinterpret_cast<uv_handle_t*>(socket), &fd) == 0) {
    uint32_t yes = 1;
    int err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, (char*)&yes, sizeof yes);
    printf("setsockopt SO_REUSEPORT err %d\n", err);
  }
  struct sockaddr_in recv_addr;
  uv_ip4_addr(listenIp.c_str(), listenPort, &recv_addr);
  uv_udp_bind(socket, (const struct sockaddr*)&recv_addr, UV_UDP_REUSEADDR);
  // ...

(for some implementations of Loop::GetLoop()