Question

One source with multiple objects
I am using MSVS 2010 and I have a C++ source-file which must compile into 2 object-files.
The diiference between those compilations is a “#define UNICODE” for one of them but not for the other.
I can’t (and don’t want to) use templates for a this.

Currently ,I use 3 source files for this in my project.
The actual source is excluded from build ,while the other 2 are wrappers around it.
Like this :

file = wrap-UNICODE.cpp

#ifndef UNICODE
#define UNICODE
#endif

#include "actual-source.cpp"
// eof

file = wrap-ANSI.cpp

#ifdef UNICODE
#undef UNICODE
#endif

#include "actual-source.cpp"
// eof

When using makefiles i can easily avoid the use of wrapper soucrces ,using different output
switches.
My question is ,I would like to know if (and how) i can do this directly in a MSVS project.

Answer 1

If i correctly understand what you want to do, this is possible.
I have MS Visual Studio 2005 Standard Edition; here is how i can do this (you might have to adjust this if you have a different version, or possibly it might even not work in your version; i hope your computer doesn’t explode 🙂 ).

The first step requires manual editing of the project file. Open the project file (it is called stuff.vcproj on my machine) and replicate the lines that mention your file:

<File
    RelativePath=".\actual-source.cpp"
    >
</File>
<File
    RelativePath=".\actual-source.cpp"
    >
</File>

Then, load the project into MSVS. Go to the Solution Explorer (Ctrl+Alt+L on my machine); the project will show two files with identical name. Open the Property Pages of each one (Alt+F7 on my machine) and add any differences you want (e.g. Preprocessor Definitions).

You must also set different names for object files: choose Output Files, Object File Name in the same window (Property Pages), and add different names (e.g. actual-source-unicode; MSVS will add the .obj extension when compiling). If you don’t do that, the two obj-files will have the same name, and one will overwrite the other.