I have a problem with a VB6 DLL and some of the behaviour leads me to wonder whether Windows is unloading it from memory after a period of inactivity. Are there any good applications/techniques for determining which DLLs are loaded into memory at a given point?
I'm using Windows XP if that makes any difference.
Download ProcessXP. You can see exactly which DLLs a process has hooks open to (along with files, etc.).
Msinfo32.exe (quick)
Use Msinfo32.exe by hitting run then entering Msinfo32.exe. Then, to see DLLs are loaded into a memory, select Software Environment then Loaded Modules category from the bottom of the left pane. Each item from the Loaded Modules category represents an application extension or a system resource that is currently loaded in memory. The right pane lists the DLL name, fully qualified path to all modules (drivers, fonts, dynamic link libraries and executable files), process, DLL version, size, date and manufacturer in memory.
Sysinternals Process Explorer (free / more robust)
Process Explorer is a GUI/device driver combination that together shows information about which handles and DLL processes have opened and loaded in memory. The unique capabilities of Process Explorer make it useful for tracking down DLL version problems or handle leaks, and provide insight into the way Windows and applications work and more.
Sysinternals Process explorerer download site
Good article where i got the quoted info: here