How to find out about system paths?

[Zack Weinberg]

On Mon, Dec 11, 2000 at 09:20:09PM -0800, Stephen C. Biggs wrote:

> My question is: how do you see what your local version has already 
> defined...

Run the compiler with -v on a trivial source file.   For instance:

$ echo > test.c
$ gcc -v -c test.c
...
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i386-linux/2.95.2/include
 /usr/include
End of search list.
The following default directories have been omitted from the search path:
 /usr/lib/gcc-lib/i386-linux/2.95.2/../../../../include/g++-3
 /usr/lib/gcc-lib/i386-linux/2.95.2/../../../../i386-linux/include
End of omitted list.
...

There's unfortunately a lot of other junk in the output, too.  You can
try -Wp,-v instead of -v but I don't guarantee it will work.

> AND how hard is it to define it system-wide?  I would like 
> to be able to have /usr/local/include come before /usr/include and 
> the "fixedheader" directory... also /usr/local/lib before /lib,

This is impossible - but as you can see, /usr/local/include is already
searched when you want it to be.  /usr/local/lib may or may not be
automatically searched depending on your linker, but -L directories
are put before the default ones, so you can get the search behavior
you want with -L /usr/local/lib (you might also need -R /usr/local/lib
depending on what you're doing...)
 
> since I would rather not have to pass this through every 
> makefile...

Sorry.  We feel that having environment variables affect the behavior
of the compiler only leads to user confusion.

zw