when GCC searches the system include directories, "/usr/include" first, or "usr/lib/gcc/include", "usr/local/lib/gcc/include"first?

[John (Eljay) Love-Jensen]

Hi Song,

> Tried [echo " " | gcc -c -xc -v -o tmp.o], seems gcc does not receive the pipe
> as its input.

echo "" | gcc -c -xc - -v -o tmp.o
.....................^
The '-' tells the compiler to use stdin for the source.

Note that parameter order is significant for the gcc command line
parameters.  Sometimes in non-obvious ways.

Sincerely,
--Eljay