What is CPP's real default include path?

[Walt Pawley]

At 12:06 PM +0200 5/5/08, Mel wrote:
>On Monday 05 May 2008 10:12:05 Walt Pawley wrote:
>> I've been fiddling with compiling nzbget-0.4.0 on a 6.3 system.
>> My initial efforts failed the configuration process for not
>> finding iconv.h. This, despite /usr/local/include/iconv.h being
>> present and supposedly in the include search path if the info
>> documentation can be believed.
>>
>> Just to see if I could learn something, I copied the
>> /usr/local/include/iconv.h to /usr/include/ and tried again.
>> After this, the configuration process completed and the
>> application seemed to "make" and "make install" just fine.
>>
>> Is there some way to ascertain what the set of default include
>> paths actually is?
>
>Even though cc has a million options, there's none that I know that prints the
>system include path (not even in -dumpspecs). However, in practice you can
>assume it's /usr/include.
>
>To make configure scripts believe you have something installed, it's not a
>good idea to copy headers.
>Look for a --with-iconv=/usr/local option and failing that, change CFLAGS and
>LDFLAGS in the environment when configuring.

Admonition understood - I was just experimenting and wanted the
file to be in a specific place without any uncertainty about
just what various "look over there" options actually do. The
reason for such a mind set is that actual behavior of cpp seems
to differ from its documentation, to wit:

  info cpp :: Header Files::Search Path reads:

  GCC looks in several different places for headers.  On a normal Unix
  system, if you do not instruct it otherwise, it will look for headers
  requested with `#include <FILE>' in:

     /usr/local/include
     LIBDIR/gcc/TARGET/VERSION/include
     /usr/TARGET/include
     /usr/include

I'm either missing something very fundamental (which I doubt
not at all) or this should be a somewhat serious problem. There
are 4944 header files in /usr/local/include/ branch on this
system that should be accessible by default but, if my
experience with nzbget is any guide, do not seem to be.
-- 

Walter M. Pawley <walt at wump.org>
Wump Research & Company
676 River Bend Road, Roseburg, OR 97470
         541-672-8975