这允许把用户内存分割为更多的段。

This allows more segmentation of user memory.

youdao

dxfer_len：数据传输的用户内存的长度。

Dxfer_len: the length of the user memory for data transfer.

youdao

现在，让我们来研究一下用户操作用户内存的内核api。

Now, let's explore the kernel APIs for manipulating user memory.

youdao

Now, if I've asked the user for a string and then a moment later I ask the user for another string, well, they're going to end up in different locations in memory just by nature of get string.

现在，如果我要用户输入一个字符串,一会儿之后我要用户输入另一个字符串，他们最终是在,不同的内存地址中。

哈佛公开课 - 计算机科学课程节选

Its name is malloc for memory allocation and what malloc does for us is we say, hmm, the user has typed in a three-letter word.

它为我们分配内存地址,它为用户输入的3个字母单词,分配地址。

哈佛公开课 - 计算机科学课程节选

That is the address in memory in the heap of the first byte that the user typed in.

那是用户输入的字符串第一个字节,内存中堆的地址。

哈佛公开课 - 计算机科学课程节选