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为什么在退出 TeX 之前，`interaction` 从 error_stop_mode 更改为 scroll_mode？

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为什么在退出 TeX 之前，`interaction` 从 error_stop_mode 更改为 scroll_mode？

请考虑以下两个摘录tex.web：

  interaction:=scroll_mode; jump_out;

"X":begin interaction:=scroll_mode; jump_out;

我无法理解背后的原因interaction:=scroll_mode。

作为参考，以下是的值interaction：

batch_mode 0 
nonstop_mode 1 
scroll_mode 2 
error_stop_mode 3

（*）的值interaction始终error_stop_mode在执行上述代码之前，因为 中的以下代码tex.web：

if interaction=error_stop_mode then @<Get user's advice and |return|@>;

答案1

它（人们可能会猜测）在那里是为了确保您之后不会再出现进一步的错误交互x。

但此时如何得到 tex 错误并不明显。幸运的是，tex.web 给出了线索​​...

@ Here we do whatever is needed to complete \TeX's job gracefully on the
local operating system. The code here might come into play after a fatal
error; it must therefore consist entirely of ``safe'' operations that
cannot produce error messages. For example, it would be a mistake to call
|str_room| or |make_string| at this time, because a call on |overflow|
might lead to an infinite loop.
@^system dependencies@>

Actually there's one way to get error messages, via |prepare_mag|;
but that can't cause infinite recursion.
@^recursion@>

事实上，如果你在默认错误停止模式下处理这个纯文本文档


\mag=2000


aaa

\break

\mag=3000 aaaa\zzzz


\bye

x 并使用然后在日志中响应未知命令错误，您将看到

? x
! Incompatible magnification (3000);
 the previous value will be retained (2000).

不兼容的磁力误差在滚动模式下处理，没有正常的交互

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