How does DelayFreeSizeMB change the behavior of my application?

Question

I just noticed that my application has a DWORD registry entry named "DelayFreeSizeMB" with a value of 64 in the registry under

HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\MyApp.exe

What does this Registry entry do to my app? I understand that "Image File Execution Options" is read by Windows right at the start of the program and it may change how Windows deals with the application. Typically this key defines GFlags (REG_SZ GlobalFlag) and application verifier settings (REG_DWORD VerifierFlags), but none of them are there.

I get only 4 google results searching for "DelayFreeSizeMB" and none of them is helpful.

Answer 1

I searched the hard disk for executables containing this word and verifier.exe (application verifier) is the "culprit". After playing with it, it turns out that there is a property for Basics / Heaps with exactly that name:

The functionality probably is:

• recently freed memory will not be given back to heap.
• instead it will be filled with a pattern.
• broken patterns can be used to identify dangling pointers and double frees

So this setting has an impact on the Windows Heap Manager. From the name it's the amount of memory that it holds back for this purpose.

If that registry value is not accompanied by a REG_DWORD VerifierFlags, it probably won't do anything.