A convenient way to find a free port is to pass in a null address, which automatically binds the socket to the local host address and USES a free ephemeral port.

找到空闲端口的便利方法是传递一个null地址，它会自动将套接字绑定到本地主机地址，并使用空闲的临时端口。

youdao

For example, if email address is null or only contains Spaces, the message "Enter your email" will be shown when the form is validated.

例如，如果email地址为空，或者只包含空格字符，那么在对表单进行验证时就会显示“Enteryour email”消息。

youdao

Data type specification: the ability to tell the UI to display the data at a given address as a specific data type - for example, this address represents the start of a null-terminated string.

数据类型规范：能够通知ui将特定地址的数据显示为具体的数据类型。例如，此地址表示以null结尾的字符串的开始。

youdao