Question

I’ve converted some legacy Fortran code to C using the f2c converter (f2c), and I’ve created a Visual Studio 10 solution on Windows 7 (64-bit). I’ve also had to link my C++ program (test.cpp, containing my main function) with the f2c library (built on my system using nmake).

The program runs, but once the end of the main function is reached, I receive the following Debug error:

Stack around the variable 'qq' was corrupted
Stack around the variable 'pf' was corrupted
Stack around the variable 'ampls' was corrupted

I am wondering if this might be due to a “correction” made by the f2c converter in the converted C (from Fortran) file:

/* Parameter adjustments */
--x1;
--xabs;
--ximag;
--xreal;
--work4;
--work3;
--work2;
--work1;
--ampls;
--pf;
--qq;
--tri;

This seems a bit odd, since all of these variables are C arrays, and I think that the f2c program is simply doing some pointer arithmetic so that index 0 in the array becomes index 1, in a similar fashion to Fortran.

I don’t know if this could also be due to something going wrong with the converted code accessing an element of the array that has not been allocated.

What is the best way to debug this error and fix it?

Answer 1

Potential reasons:

• This error is usually related to writing outside the bounds of an array (dynamic or static array). This error can occur by writing\getting a value in a -ve index or index >= size_of_array.
• This error also accurs if your pointer is not set to its correct location. (e.g. ptr = 0, ptr = 55, points to deleted (released; or has been free) memory, or any invalid address)

Best way to debug your error in my mind is to debug your prorgam step-by-step and watch those pointer values. There must be some wrong with them.