bash builtin读取：超时后未设置变量

Question

来自bash手册页：

read [-ers] [-a aname] [-d delim] [-i text] [-n nchars] [-N nchars]  [-p  prompt]  [-t
 timeout] [-u fd] [name ...]
       ...blabla...
       -t timeout
              Cause read to time out and return failure if a complete  line  of  input
              (or  a  specified  number of characters) is not read within timeout sec‐
              onds.  timeout may be a decimal number with a fractional portion follow‐
              ing the decimal point.  This option is only effective if read is reading
              input from a terminal, pipe, or other special file;  it  has  no  effect
              when reading from regular files.  If read times out, read saves any par‐
              tial input read into the specified variable name.  If timeout is 0, read
              returns  immediately,  without trying to read any data.  The exit status
              is 0 if input is available on the specified  file  descriptor,  non-zero
              otherwise.   The  exit  status  is  greater  than  128 if the timeout is
              exceeded.

我希望read -r -t 1 VAL等待我的输入，以输入结束，然后保存到$ VAL 或者如果我输入＆＃34;哇＆＃34;并且不要按回车键。 read会等我1秒，然后返回代码＆gt; 128 那么[$ VAL ==＆＃34;哇＆＃34; ]将是真的。

但是在我的测试中，只需等待1秒，然后忽略我的输入，而不是设置＆＃34;部分输入＆＃34;到$ VAL

[root tmp]# echo $BASH_VERSION
4.3.42(1)-release
[root tmp]# V=1
[root tmp]# echo $V
1
[root tmp]# IFS= read -t 1 -r V
wow[root tmp]# wow^C            # <---- ???
[root tmp]# echo $?
142
[root tmp]# echo $V
                                # <---- ???
[root tmp]# 

从手册页，我认为结果应该是：

[root tmp]# echo $BASH_VERSION
4.3.42(1)-release
[root tmp]# V=1
[root tmp]# echo $V
1
[root tmp]# IFS= read -t 1 -r V
wow[root tmp]# ^C               # <---- !!! read will "eat" my input
[root tmp]# echo $?
142
[root tmp]# echo $V
wow                             # <---- !!! and set V=`my partial input`
[root tmp]# 

我误解了什么吗？为什么＆＃34;哇＆＃34;不存入$ V？

THX。