Flock

pub const Flock = switch (native_os) {
    .linux => linux.Flock,
    .emscripten => emscripten.Flock,
    .openbsd, .dragonfly, .netbsd, .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos => extern struct {
        start: off_t,
        len: off_t,
        pid: pid_t,
        type: i16,
        whence: i16,
    },
    .freebsd => extern struct {
        /// Starting offset.
        start: off_t,
        /// Number of consecutive bytes to be locked.
        /// A value of 0 means to the end of the file.
        len: off_t,
        /// Lock owner.
        pid: pid_t,
        /// Lock type.
        type: i16,
        /// Type of the start member.
        whence: i16,
        /// Remote system id or zero for local.
        sysid: i32,
    },
    .illumos => extern struct {
        type: c_short,
        whence: c_short,
        start: off_t,
        // len == 0 means until end of file.
        len: off_t,
        sysid: c_int,
        pid: pid_t,
        __pad: [4]c_long,
    },
    .haiku => extern struct {
        type: i16,
        whence: i16,
        start: off_t,
        len: off_t,
        pid: pid_t,
    },
    // https://github.com/SerenityOS/serenity/blob/2808b0376406a40e31293bb3bcb9170374e90506/Kernel/API/POSIX/fcntl.h#L54-L60
    .serenity => extern struct {
        type: c_short,
        whence: c_short,
        start: off_t,
        len: off_t,
        pid: pid_t,
    },
    else => void,
}