How can you find memory leaks in long-running applications?

Check out Valgrind. It's a fantastic tool for detecting memory leaks and other memory issues, and it's widely regarded in the community.

Honestly, if your app is running for a long time and having memory leaks, sometimes it's just easier to automate a weekly restart. Some leaks might not even be in your code, so you can't always control it. I've had C# and VB apps that ran for years without major issues. If you do want to check your allocations with malloc, try implementing a debug statement to count them and make sure allocations and free calls match up. But if all else fails, consider using a language that manages memory for you.

One solid approach is to use a memory profiler while your app is running to collect data, but keep in mind this could affect performance if you're doing this in a production environment. If possible, try this in a dev setup with ample data to see if anything stands out. Also, be cautious with any unsafe or native resources you might be using, since those can behave poorly. Look for multiple object references too, and don’t forget about event subscriptions that can keep your objects alive longer than necessary. Using environment variables to toggle between old and new code can help you track down issues.

Using memory dumps can give you insight into the size and number of allocations happening in your app. This can be a straightforward method to start tracking down leaks, especially if you know what to look for.