Books on portibility between Unixes?

[Jesse W. Asher]

I'd like to write some software that is very portable between different
types of Unix.  I'm not just talking about BSD vs. SystemV, but also how
different system's compilers handle various functions differently.  I've
written a program that I've compiled on a 386 running SysV, an NCR tower
running SysV, and a SparcStation running SunOS, and I had to make
modifications all three times.  So first, I'd like to find out what
functions are most portable, and then find out how to use directives
(ifdef, ifndef, etc) to make the software as portable as possible.  I'd
like to take the tact that I want to eventually post this software to
the net, but I don't know how to make it as portable as possible.  I've
looked at various programs already posted on the net (Cnews, elm, etc)
and that has given me ideas.  But does anyone know of a good publication
on this type of programming?


-- 
      Jesse W. Asher        NIC Handle:  JA268         Phone: (901)386-5061
                       Health Sphere of America Inc.
	       5125 Elmore Rd., Suite 1, Memphis, TN 38134
 Internet: jessea at homecare.COM                 UUCP: ...!banana!homecare!jessea