isnan for ppc def help

[Scully, Maureen]

VxWorks user -
	Do you have any suggustions on how is can resolve the undefined
symbol, isnan for the ppc?
Some background info:
	I am using Tornado for VxWorks & Seawind for X/Motif/OpenGL support
for VxWorks running on a PPC - power PC. Found your knowledgeable responses
on a bulletin board when I search.  
I think that someone else must had the same problem or can advise me on
porting software to the VxWorks/PPC environment. VxWorks/PPC Tornados
Windshell outputs: undefined symbols: isnan, equal, ent, directory,
valid_path, and remove_dir...  These symbols are prototyped with a #ifdef
unix and #ifdef mac differently. In these header files need to define a
similar definition #ifdef VXWORKS for the PPC. isnan wrapper has the highest
concern. 
I not sure don't understand why isnan differs in MAC and Unix defs. How then
does VxWorks needs to do to resolve these symbols. Tornado's C++ compiler
does not seem to resolve after I tried similar definitions during build
because later during run time, spawning the loaded executable this problem
still shows up. The NFS, network file system should help in resolving  the
variations in mkdir, chdir, rmdir. Not the comparable to isnan, valid_path,
directory, ent, and equal under VxWorks.
I think I need to load these symbol definitions in a *.o file, but I don
understand them. 
I was hoping someone could share their insight into this symbol issue? 

Thank you.

Maureen Scully
Maureen Baxter Scully                               
Prin. S/W Design Eng.                            AIEWS Integration Team
Lockheed Martin OR & SS                     P.O. Box 4840 EP6-201
telephone: (315) 456-1371                   Syracuse, New York 13221
fax: (315) 456-1680                               email:
Maureen.Scully@lmco.com