How to force the build to be out of date, when a text file is modified?

Question

The Scenario
My project has a post-build phase set up to run a batch file, which reads a text file "version.txt". The batch file uses the information in version.txt to inject the DLL with a version block using this tool.

The version.txt is included in my project to make it easy to modify. It looks a bit like this:

@set #Description="TankFace Utility Library"
@set #FileVersion="0.1.2.0"
@set #Comments=""

Basically the batch file renames this file to version.bat, calls it, then renames it back to version.txt afterwards.

The Problem
When I modify version.txt (e.g. to increment the file version), and then press F7, the build is not seen as out-of-date, so the post-build step is not executed, so the DLL's version doesn't get updated.

I really want to include the .txt file as an input to the build, but without anything actually trying to use it.

If I #include the .txt file from a CPP file in the project, the compiler fails because it obviously doesn't understand what "@set" means.

If I add /* ... */ comments around the @set commands, then the batch file has some syntax errors but eventually succeeds. But this is a poor solution I think.

So... how would you do it?

Answer 1

This may be too "hacky" but this might work:

1. Write a quick Perl (etc.) script to check version.txt has been updated.
2. If the file has been modified, have this script update a dummy source file that is compiled with your project.
3. Run the script as a pre-build event.

This way if the script sees that the file has changed, it will change the other one, which will force a re-build.

Hacky, but try it if you're scraping the bottom of the barrel.

Answer 2

This works in VS2005. If you're not using that, some of the settings may be in different places or with different names.

Add the text file to your project, right click on it in the Solution Explorer and select 'Properties'. Under Configuration Properties > General make sure that the file is not excluded from the build. Under Custom Build Step > General, put your existing post-build command as the Command Line setting. Make sure you specify your .txt file as the output file. Now F7 should spot changes to the text file and run your batch file.