prctl

pub fn prctl(option: PR, args: anytype) PrctlError!u31 {
    if (@typeInfo(@TypeOf(args)) != .@"struct")
        @compileError("Expected tuple or struct argument, found " ++ @typeName(@TypeOf(args)));
    if (args.len > 4)
        @compileError("prctl takes a maximum of 4 optional arguments");

    var buf: [4]usize = undefined;
    {
        comptime var i = 0;
        inline while (i < args.len) : (i += 1) buf[i] = args[i];
    }

    const rc = system.prctl(@backingInt(option), buf[0], buf[1], buf[2], buf[3]);
    switch (errno(rc)) {
        .SUCCESS => return @intCast(rc),
        .ACCES => return error.AccessDenied,
        .BADF => return error.InvalidFileDescriptor,
        .FAULT => return error.InvalidAddress,
        .INVAL => unreachable,
        .NODEV, .NXIO => return error.UnsupportedFeature,
        .OPNOTSUPP => return error.OperationUnsupported,
        .PERM, .BUSY => return error.PermissionDenied,
        .RANGE => unreachable,
        else => |err| return unexpectedErrno(err),
    }
}