[Mingw-users] Mixing GFortran and G++, problem with memory corruption

[Richard U. <Ric...@Ul...>]

Hello,

To allow a legacy Fortran program to use a third-party DLL, we wrote 
a C++ wrapper.  The C++ files are compiled with g++,  Fortran files 
with GFortran, and the whole collection linked with g++.  I'm using 
MinGW32 4.5.0, installed using MinGW-Get version 0.1-alpha-5, on Windows XP.

After some struggles, it worked.  The main issue, of course, was to 
resolve all the mangled names and to be careful with string 
parameters.  (Actually, as of now I've eliminated all string parameters.)

However, when I add calls to the C++ functions from within deeply 
nested nested Fortran do-loops, I run into problems with the Fortran 
code and/or data space getting corrupted after many iterations.  This 
happens whenever the C++ functions are called, even if they do 
nothing other than return.  Weird things happen like variables change 
value when they shouldn't,  the loops don't stop when they should, 
"write" and "print" statements trigger a SIGSEGV, and so on.  (I can 
tell from running it in a debugger.)   If I comment out the C++ calls 
that do nothing, the errors don't occur.  Therefore, it would seem to 
be something to do with setting up the stack frame to make the call.

The g++ compilations use the following options: -mtune=generic -c -g

The GFortran compilation uses -g -c -fbounds-check  -finit-local-zero 
-ffpe-trap=zero,invalid,underflow,overflow

The final linking line uses  g++  -mtune=generic -static -g -o

Might anyone have some ideas about what it going on, and how to fix it?


Thanks,
Richard U