Energizer Project: Keeps Building and Building

Michael Geary | Thu, 2004-08-12 15:37

Did you ever have a Visual C++ project that won’t stop building? It builds OK, but if you start the debugger or do another Ctrl+Shift+B, it says it’s out of date and wants to build again? Every time?

This happened to me and I was stumped. There was nothing in the Output window to tell me what was wrong. It looked like a perfectly successful build:

------ Build started: Project: Test,
Configuration: Debug Win32 ------

Compiling resources...

Build log was saved at
Test - 0 error(s), 0 warning(s)

-------------- Done --------------

    Build: 1 succeeded, 0 failed, 0 skipped

The only problem was it compiled those resources every time. It never thought they were up to date.

I tried some Google searches. Nothing. This was annoying me, and the rest of my team.

Finally, out of sheer frustration, I Ctrl+clicked on that “Build log” link, like the helpful tooltip suggested.

Oh. Now it tells me:

Compiling resources...

Test : warning PRJ0041 : Cannot find missing
dependency 'ICON_FILE' for file 'Test.rc'.
Your project may still build, but may
continue to appear out of date until this
file is found.

That gives me a desperately needed clue. Looking at Test.rc, I see that I’d coded:

#ifdef DEMO
    #define ICON_FILE "Icons\Demo.ico"
    #define ICON_FILE "Icons\Full.ico"


Well, it sounded like a good idea at the time, honest.

The resource compiler has no problem with this, but apparently the dependency checker can’t handle it.

Changing it to this fixed it:

#ifdef DEMO
    1 ICON DISCARDABLE "Icons\Demo.ico"
    1 ICON DISCARDABLE "Icons\Full.ico"

The Moral:

  • The information you need may be hiding behind a link. Just because the Output window has always told you about build problems doesn’t mean it will tell you today.
  • If your product has an Output window that almost always provides complete information, fix it so it always does.