Adding and Editing Filters

Selecting the Add button in the Memory Debugging Data Filters dialog (Figure 66), launches the Add Filter dialog, Figure 67.) Similarly, clicking the Edit button launches a nearly identical window.)

Figure 67: Add Filter Dialog Box

The name of the filter. This name will appear in the Memory Debugging Data Filters dialog box.

In Figure 67, notice that one filter is named “Function Name contains _S_chunk_alloc”. This is the name created by MemoryScape when you use the context menu to add a function name. Similarly, you’ll see a filter named “Line Number = 490”.

Creates a shared filter. Shared means that anyone using MemoryScape can use the filter.


NOTE >> This button appears only if you have write permissions for the MemoryScape lib directory.

Adds a blank line beneath the last criterion in the list. You can now enter information defining another criterion for this filter in this new line.

Deletes the selected criterion. To select a criterion, select the number to the left of the definition.

Changes the order in which criteria appear in the list. Criteria are applied in the order in which they appear, so you should place criteria that remove the most entries at the top of the list. Filtering can be a time-consuming operation, so this can increase performance.

For more than one criterion, the selected radio button indicates if any or all of the criteria have to be met.

Removes an entry when the entry matches any of the criteria in the list.

Removes a memory entry only if it fulfills all of the criteria.

Removes an entry only if the criteria is valid on an entry that is also the allocation focus.

The allocation focus is the point in the backtrace where MemoryScape believes your code called malloc().

For example, if you define a filter condition that says Function Name contains my_malloc and set this entry to allocation focus entry only, MemoryScape removes entries only whose allocation focus contains my_malloc. That is, it removes only allocations that originated from my_malloc.

In contrast, if you set this entry to all backtrace entries, MemoryScape removes all blocks that contain my_malloc anywhere in their backtrace.

Applies filter criteria to all function names in the backtrace.

A filter is made up of criteria. Each criterion specifies what to eliminate from the list. Each criterion has three parts: a property, an operator, and a value. For example, you can look for a Process/Library Name (the property) that contains (the operator) strdup (the value).

When evaluating an entry, MemoryScape can look at one of eight properties for one criterion, Figure 68. Select one of the items from the pulldown list. These items are:


Backtrace ID	PC
Class Name	Process/Library Name
Count	Size (bytes)
Function Name	Source File Name
Line Number

Indicates the relationship the value has to the property, Figure 68. Select one of the items from the pulldown list. If the property is a string, MemoryScape displays the following list:


contains	not contains
ends with	starts with
equals	not equals