FIX: Win32 handles leak detection

Table of Contents

Affected By These Platforms

Description

How to detect memory leaks in Windows applications?

What does nativeleakdetector do for memory leaks?

Memory leaks are a class of pesky bugs where an application does not release memory when it is no longer needed. Over time, memory loses the influence of the application and the operating system. A large leak can cause unacceptable response times due to heavy paging. At some point, the application will crash along with other parts of the operating system.

Windows will make all free memory allocated by the application available at the end of the process so that short-term applications do not have a significant impact on overall system performance. However, leaks that are triggered in processes like services or even In long-running Explorer plug-ins, in many cases can seriously affect the reliability of the system and will probably force the user to change Windows so that the device can be used again.

There are several ways that applications can allocate memory on their behalf. Any type of collation can leak if not used immediately. Here are some examples of common cartographic models:

Create a heap of memory using the special function heapalloc or its educational C / C ++ equivalents malloc or new.
I would say direct assignments from the operating system via the VirtualAlloc function.
Kernel descriptors created using Kernel32 APIs such as CreateFile , CreateEvent , CreateThread hold the kernel memory as “ready applications “
GDI USER and handles managed through the User32 and Gdi32 APIs (10,000 handles are allocated to each process by default)

Best Practices

Does GDI leak detection work on newer versions of Windows?

Because some newer versions of Windows require a slightly different approach to handling GDI leaks, the author uses updated methods for these business systems. He develops and explains other tools for detecting and stopping GDI leaks in applications running on Windows XP, Windows 2000, that is, Windows NT.

Tracking the bio-consumption of your app in creativity over a period of time is the first step in diagnosingNostics and diagnostics of memory leaks. Use Windows Task Manager and add hints: follow commit size, handles, custom and GDI objects. This is a great way to compare your application and track resource consumption over time.

How is cwindowdc used to detect resource leaks?

The following Microsoft tools provide more detailed information and can help identify and definitively diagnose leaks for our various mapping types in your end-user application:

Performance Monitor and Resource Monitor are slots in Windows 7 that can track graphics and resource usage over time.
Most versions of Application Verifier can scan for heap leaks on Windows 7.

The

UMDH, which was part of the Windows Debugging Tools, analyzes the amount of heap memory for a given process and can help find leaks and other strange usage patterns.

Xperf is a sophisticated and easy-to-use analysis tool that supports packet distribution tracing.
CRT Debug Heap keeps track of global allocations and can help you oncework your own valuable heap debugging capabilities.

Certain coding and design techniques can limit many leaks in your code. Smart

Use clauses in C ++ code to allocate heap and Win32 resources such as kernel HANDLES. The C ++ Standard Library provides your auto_ptr class for heap allocation. For other basic types, you will need to write your own classes. The ATL library offers a rich set of automatic resource management classes that are available for both heap objects and kernel descriptors.
Use built-in compiler functions such as _com_ptr_t to encapsulate your COM interface pointers directly into smart pointers and to count studies. There are similar classes due to different COM data types: _bstr_t still _variant_t
Watch out for unusual uses of your .NET code on storage devices. Managed code is not immune to memory leaks. See “Tracking Managed Memory Leaks” for how to find garbage collector leaks.
Pay attention to the templates requests in client-side web code. Circular references between COM objects and scripting engines such as JScript can lead to significant leaks in web applications. “Internet Explorer Leak Troubleshooting and Templates” provides more information about these types of related leaks. You can use the JavaScript memory leak detector to debug accidental memory leaks in your code. While Windows Internet Explorer 8 bundled with Windows 7 fixes most of these problems, older browsers are still directly prone to these errors.
Avoid using multiple inference methods for a function. Assignments to which objects in the functional area have been assigned should actually be freed in a specific block, perhaps at the end of the function
Make sure you don’t use exceptions in your code if it is not efficient to free all local variables. If you are using native free passes then all your homework is in one __finally block. When using C ++ exceptions, all heap and descriptor shares must be surrounded by intellectual pointers.
Do not delete or dump the absolute PROPVARIANT object without calling the PropVariantClear

function