问题
Whenever I exclude a .h file from the build and then re-include it later, the icon for the .h file in the Project Explorer will have a push-pin adornment. I looked on the CDT User Guide but it's not on their list of icons. What does the push pin mean?
回答1:
You may have uncovered a small bug in CDT!
You did not include an image in your original question so I'm going to propose that the icon overlay you are seeing is not a push-pin, but an indicator that the properties for this element (the include file) have been modified (it looks like a little wrench). When you exclude the element it gets an overlay indicating exclusion, when you re-include the element you see the wrench overlay. This is the bug since you have returned the element to its unmodified state. The wrench overlay should not be displayed in this case.
If you try excluding C source file you'll see the exclusion overlay, and when you re-include the C source file the exclusion overlay is removed and only the original icon (with no overlay) is displayed.
(I tried this using CDT 7.0.0)
回答2:
I had different versions of a cpp file that I wanted to try. By interchanging them, the newly included file had such a small wrench in the icon. It appears to be a small bug.
Solution:
create new file, copy contents, delete old file, rename new file to the name of the old file, done.
来源：https://stackoverflow.com/questions/5209388/what-does-the-push-pin-icon-adornment-mean-in-eclipse-cdt