[Mingw-users] Invalid page fault in DLL

[Andrew G. <And...@np...>]

I am writing a Python extension (a DLL) in C++ which itself uses
functions from within a commercial DLL (IEEE_32M.DLL). Most of the
functions work, but one of the functions (receive) causes an "invalid
page fault" apparently from within the DLL. I'm using GCC-3.2.1 and have
already found that the code works with Borland C++. The cause of the
problem may be related to the fact that receive is the only function
that returns a string. A similar function "transmit" for sending a
string works ok.


From the header file for the DLL supplied by the manufacturer:

extern "C" {
extern long int  _cdecl ieee488_receive (char  *,unsigned long,unsigned
long  *,long int  *);
}

#define receive(s,maxlen,len,status)    ieee488_receive((char  *)
(s),maxlen,(unsigned long  *) len,(long int  *) status)



\\ In my code:
  long int status;
  long int GPIB_NCharReceived;
  char *Work;
  Work = new char[256]; 
  long int maxlen = 255;


\\ The call looks like this
      receive(Work,maxlen,&GPIB_NCharReceived,&status);


From the IEEE_32M.DEF created using pexports (extract only gives receive
function for brevity)

LIBRARY IEEE_32M.DLL
EXPORTS
DllMain
IEEE488_RECEIVE
_ieee488_receive
_ieee_receive@16
ieee488_receive


I've tried a variety of compiler/ linker options but with no luck.
Currently:
 
extra_compile_args=['-O0','-march=i586','-malign-double'],
                      extra_link_args=['-mthread','-mms-bitfields'],


Does anyone have any ideas?

Andrew.

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