I have a project that uses two third party libraries, both of which make use of TCHARs in their header files. Unfortunately one library is complied as multi-byte (call it library a), and the other is compiled as Unicode (call it library b).
Now the way I understand it is that TCHAR is replaced by the precompiler with either wchar or char depending on the build options. So when library a was compiled any method that takes a parameter of type TCHAR was set to expect a parameter of type char, and methods in library b are set to expect a parameter of type wchar.
Unfortunately my consuming application has to pick a character set too. If I pick Unicode then the header file I have included for library a tells me that the method wants a wchar, because when I compile the TCHARs in the header they are interpreted as wchars. This includes TCHARS defined inside of structures. I have confirmed this behavior in practice, when I allocate and pass a TCHAR buffer I get back garbage because it fills my wchar buffer with multi-byte data.
My questions are: Is there a clean way to consume both of these libraries in the same application? Am I maybe doing something wrong with how I'm using these libraries?
Assuming you're not using too many class/function in either one of these libraries, I would wrap one of the library completely. Let's say if you decided to use mbc in your app and wrap library b (unicode), your wrapper header file can use wchar_t instead of TCHAR so #define will not affect your interface. Inside your wrapper's cpp file where you #include library b's headers, you #define TCHAR to match library b. No code other than your wrapper should be allowed to see library b.
If you're using more than a few class/function in both of these libraries, maintaining the wrapper code will quickly become a problem of its own.