nt-user-call

This library provides bindings to all functions accessible via the NtUserCall* family of system calls.

Up until Windows 11, a bunch of system calls were grouped together into a dispatch table, apfnSimpleCall, and invoked by calling a dedicated family of syscalls with the respective index of that function. For example, CreateMenu would be called via NtUserCallNoParam(0);, with 0 being its index in the dispatch table in all supported Windows versions. However, the number of functions and their indices in that table varied between Windows versions, Windows versions prior to Windows 10 did not export the NtUserCall* family of syscalls, and the dispatch table was removed in Windows 11 in its entirety, with all functions being converted to syscalls exported from win32u.dll.

This library provides a unified interface to all of these functions by abstracting away of the differences between indices, syscall availability and exported syscalls in Windows 11.