[cfe-dev] Trying to understand some test "... 2>&1 >/dev/null | ..."

[Nuno Lopes]

> There is a bunch of failures caused by this kind of tests on windows, such
> as Preprocessor\include-directive1.c. Here an example of a test command:
> // RUN: clang-cc -E %s -fno-caret-diagnostics 2>&1 >/dev/null | grep 'file
> successfully included' | count 3
>
>>From what I understand, first stderr is redirected to stdout and then 
>>stdout
> to /dev/null, meaning if I understand thing well that both stderr and 
> stdout
> goes into /dev/null and are not passed to the next process in the pipe. So
> what it supposes to go in the following pipe? Obviously there is something 
> I
> don't know...

nops. that means that stderr is passed through the pipe and stdout is 
discarded. The forwarding of fds is done in the specified order (and it 
matters).
Nuno