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EiffelStudio

# Introduction

The call stack is the list of features that have been entered and not exited since the program started. It is a stack since before a feature exits, all the features it calls must exit too. The last entered feature is the top of the stack whereas the program root feature is its bottom.

There is one level in the call stack, apart from the top, that has a special status and corresponds to a special call stack element. It is the level to which all debugging tools refer. It is user-definable, so that it is possible to move along the call stack and have information about any level, by setting each level as the current call stack level in its turn.

To keep trace of a call stack (for example in order to indicate to other people where a problem occurred), it is possible to save the call stack to a text file.

Information concerning the call stack is spread over several graphical components:

- Information concerning the call stack in its globality is displayed in the call stack tool.
- Information concerning the current call stack element is displayed in the feature tab, the locals view, and is used to provide the expressions evaluations contained in the Expression evaluator tool.