PipeList

Did you know that the device driver that implements named pipes is actually a file system driver" In FACT, the driver`s name is NPFS.SYS, for "Named Pipe File System". What you might also find surprising is that its possible to obtain a directory listing of the named pipes defined on a system. This fact is not documented, nor is it possible to do this using the Win32 API. Directly using NtQueryDirectoryFile, the native function that the Win32 FindFile APIs rely on, makes it possible to list the pipes. The directory listing NPFS returns also indicates the maximum number of pipe instances set for each pipe and the number of active instances. To demonstrate the listing of named pipes I`ve written a program called PipeList. PipeList displays the named pipes on your system, including the number of maximum instances and active instances for each pipe.