pointer to class in VC++ 6

[TxITGuy]

Hi all,

I am attempting to convert IJG's JPEG code from C to C++ so that I can use it in an MFC windows program, and have come across a confusing problem.

The original code uses a series of structures to mimic the class, property, method layout of C++ programs. I am converting these structures into true C++ classes, and have had good success most of the time. However, the system IJG used has one class that includes pointer member variables to three other classes (an error manager, a memory manager, and a progress monitor).

Each of these classes have several methods that accept pointers to the aforementioned class as a parameter. I use a typedef in the class's ".h" file to create a "common_ptr" type. I.e. "typedef CCommon* common_ptr;".

When I try to compile this though, having made sure to include "common.h", I get the following errors:

MemMgr.h(166) : error C2143: syntax error : missing ';' before '*'
MemMgr.h(166) : error C2501: 'common_ptr' : missing storage-class or type specifiers
MemMgr.h(175) : error C2061: syntax error : identifier 'common_ptr'

The third error is at the function prototype that accepts common_ptr as a parameter.

If I remove the #include for "MemMgr.h" from the "Common.h" file, these errors go away ... but I get the same errors in "Common.h" (for good reason, because the class definitions it needs are no longer available to it).

How do I resolve these errors and still keep the pointer parameters that some of CMemMgr's methods require in order to work?

Thanks for your help.