type mismatch in conditional expression...used to compile fine

["Robby Dermody (Nova)" <nova at pimpsmack dot org>]

Hail to the Compiler Gods!

I've tried the below using both gcc 2.95.2 and the 1/3/2001 snapshot of
gcc from codesourcery, I get the same errors with both.
I'm compiling with -Wall.

-Basically, I have the following macro directive declared at the head of
my source file:
#define PMAP (MapType == MFF ? ((mff*)pMap) : (MapType == MTF ?
((mtf*)pMap) : ((mtf_MT*)pMap)))


-I also have this named enumeration in my source file:
enum LOADMAP_MAPTYPES
{
   MFF,
   MTF,
   MTF_MT
};

-Finally, one of the functions containing the statements that give me
the error is:
static void* Internal_Action_LoadMap(enum LOADMAP_MAPTYPES MapType, int
fdMapFile, void* pMap)

As you can see from the function parameter list, MapType and pMap are
valid, statements like if(MapType == MFF), etc. are fine, of course.

The problem comes when I have something like
"PMAP->Header.NumProhibitedMTs", using that macro to cast pMap to the
appropriate type, depending on what MapType is set for, and then
dereference it. I faintly remember gcc not giving me warnings/errors
about this when I last touched this code awhile ago...with both of the
gcc's I've tried, I get the following:

shared/map.c:92: warning: pointer type mismatch in conditional
expression
shared/map.c:92: warning: dereferencing `void *' pointer
shared/map.c:92: request for member `Header' in something not a
structure or union

It seems that the conditional operator wants the latter two operands of
the same type, and doesn't like that casting I'm doing. My question is,
is this a gcc-specific feature, or part of the C spec saying I shouldn't
do such a thing. (It might look like an ugly hack I've done, but it does
save me from reproducing a lot of code in this case). Is there a
pragma/switch I can throw to gcc to stop complaining about this, or is
what I'm trying to do considered just plain wrong? I'd really like to
keep using -Wall and stay as compiler-independant as possible...

In my search on the web for some information, I've found few useful
things, most useful being the following thread:

http://gcc.gnu.org/ml/gcc-bugs/2000-07/msg00093.html



Any help is appreciated, maybe I'm just being stupid...

Robby
-- 
Robby Dermody (Nova)
Avalon Entertainment - http://www.avalonent.org
BOPS, Inc. - http://www.bops.com
nova@avalonent.org - http://www.pimpsmack.org/~nova
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