portability thing?

[Dan Stromberg]

Hi folks.

I'm working on building some software, some of which is written in C++,
for a researcher here at the University.

I have an extensive background in C and python, but I haven't done much
with C++ - I kind of mostly abandoned C++ some time ago, when I coded a
project in C++, and some of my coworkers refused to use it -because- it
was in C++.

So anyway, I'm working on building a library in C++, and although the
library builds fine with g++, it does not build with IBM's xlC_r (C++,
reentrant).  The OS I'm on is AIX 5.1 ML 4.

I was fine with building the library with g++, but the researcher really
wants it built with xlC_r, because he believes (and is probably right)
that xlC_r will produce faster code, and produce a library that can be
linked with either xlC* or g++, while a library compiled with g++ would
appear to be only linkable, on this platform, with g++.


The error I get with xlC_r is:

xlC_r -qlanglvl=extended -q64 /usr/local/lib/libmalloc.a -DHAVE_CONFIG_H -I. 
-I. -I. -I. -I./gl -I/usr/local/include -I/usr/local/include/libxml2 -I./GNU -g 
-c -M RValue.cc  -DPIC -o .libs/RValue.o
"RValue.cc", line 176.39: 1540-0016 (S) The expression must be an integral 
constant expression.
gmake[2]: *** [RValue.lo] Error 1


The offending line of RValue.cc is:

    BaseType **argv = new (BaseType *[argc + 1]);


Unfortunately, that "*[argc + 1]" wouldn't mean a great deal in C, and I
suspect it's not going to be in many C++ books, because it seems likely
that it's not portable C++, but rather a g++ extension of some sort? 
Moreover, it seems a difficult thing to google for due to it being a bunch
of special symbols, rather than keywords...

Anyway, I've tried a few things to get this to build with xlC_r, including
cranking up the permissiveness of what language extensions xlC_r accepts,
but it doesn't seem to be helping.

Does anyone have any suggestions for me?

Thanks!