Peter's Blog

I've been looking into why the make facilities in my Eclipse/CDT install are not working (I try a make and nothing happens). I found a log file in my workspace folder called /.metadata/.log and the log file contains this:

!ENTRY org.eclipse.core.resources 4 2 2007-11-28 11:13:09.401
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".
!STACK 0
java.lang.NullPointerException
  at org.eclipse.cdt.managedbuilder.internal.core.CommonBuilder.build(CommonBuilder.java:520)
  at org.eclipse.cdt.managedbuilder.internal.core.CommonBuilder.build(CommonBuilder.java:506)
  at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:624)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
  at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:166)
  at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:273)
  at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:354)
  at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:494)

So the java is hitting some runtime error and the architecture is so poor that the error is not reported to me, I have to sit there wondering why nothing is happening.

I searched through the eclipse plugin directory and found zip files that contained the source code. The error in the log pointed me to this line:

IConfiguration activeCfg = info.getDefaultConfiguration();

so my guess was that getDefaultConfiguration was returning a null. This tied in with an observation I made that the "Build Configurations" menu in Eclipse/CDT had all it's items greyed out, including 'Manage..'. I decided that it was probably all because I hadn't set up my CDT project properly. I created a new CDT project, imported my source into it, deleted the old project, renamed the new project to match the old and tried it out. Voila, make ran and the output was in the console.

Lessons learnt:

• Projects may work with a number of perspectives (e.g. C/C++, Ruby etc) and each perspective wants it's configuration data within the project set up properly. At the same time, they seem only to set these configurations up when you create new projects, adding configuration data to an existing project when you use a new perspective appears to be up to the individual plugins: RDT, the ruby development plugin has an 'add ruby nature' option in the project menu to do this.
• Because Eclipse is written in java it comes with all the source code. This means that even if some of it is a bit flaky one stands a good chance of working around the problems.

Ok, I'm an Eclipse noob and didn't set my project up correctly but the environment really ought to have handled this better.