[eqvinox]

This affects -to my best knowledge- only bind()ing, not outgoing connect()ing. As the name implies, really.

(I should try this, not entirely sure tbh.)

It won't help you though if the resolver library gives you a ::ffff:ma.p.p.ed address (yes they can do that), then you just fail to connect…

[aaronmdjones]

I did try this. connect(2) with an IPv4-mapped IPv6 address on an AF_INET6 socket with IPV6_V6ONLY set on it fails.

[eqvinox]

Very good to know, Thanks for trying!