Poll on macOS 10.12 is broken

Re:Poll on macOS 10.12 is broken by LukeShu on Tuesday October 11, 2016 @01:17PM (#12686371)

POSIX leaves it ambiguous whether you need to clear it or not.

About sockaddr_in, POSIX-2001, 2004 edition[1] has to say:

    10004     The <netinet/in.h> header shall define the sockaddr_in structure that includes at least the
    10005     following members:

    10006       sa_family_t     sin_family    AF_INET.
    10007       in_port_t       sin_port      Port number.
    10008       struct in_addr  sin_addr      IP address.

So implementations are free to add whatever extra members they feel like.

However, about IPv6 it says:

    10016     The <netinet/in.h> header shall define the sockaddr_in6 structure that includes at least the
    10017     following members:

    10018       sa_family_t      sin6_family     AF_INET6.
    10019       in_port_t        sin6_port       Port number.
    10020       uint32_t         sin6_flowinfo   IPv6 traffic class and flow information.
    10021       struct in6_addr  sin6_addr       IPv6 address.
    10022       uint32_t         sin6_scope_id   Set of interfaces for a scope.

    10023     The sin6_port and sin6_addr members shall be in network byte order.

    10024     The sockaddr_in6 structure shall be set to zero by an application prior to using it, since
    10025     implementations are free to have additional, implementation-defined fields in sockaddr_in6.

So raimue's point is explicitly true for sockaddr_in6; while it is left ambiguous whether the (allowed) implementation-defined members of sockaddr_in must be initialized.

[1]: The current UNIX standard is UNIX V7, which corresponds to SUSv4, which corresponds to the POSIX-2008. However, macOS is certified UNIX under the previous version, UNIX 03, which corresponds to SUSv3, which corresponds to POSIX-2001.

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Re:Poll on macOS 10.12 is broken by kazinator on Tuesday October 11, 2016 @01:51PM (#12686743)

For IPv6 that makes a modicum of sense, because IPv6 has additional fields in the address not directly related to identifying the endpoint, and these have been historically in churn.

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Re:Poll on macOS 10.12 is broken by kazinator on Wednesday October 12, 2016 @12:35PM (#12694333)

There is no ambiguity: there is no requirement in POSIX that the additional members of struct sockaddr_in be initialized by the application. The requirements are given for sockaddr_in6 only.

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