Calling System Level Functions from various Languages

These are experiments about calling low level system functions

HelloSDL3.asm

• Assembly program that manually writes import address table (IAT)
• for sdl3.dll, msvcrt.dll , user32.dll, kernel32.dll then
• shows how to call a function from these .dlls
• also writes macro for sprintf and messagebox combination
• Compile this code sdl3 must be placed same directory of output executable and requires a Flat Assembler
• fasm.exe HelloSDL3.asm

HelloWindows.py

• Python script that uses cffi for C declarations for Windows types
• then shows how to pass a pointer, integer, wide char, callback functions(WNDPROC) to other functions
• Creates a Win32 Window and Button inside it.
• pip install cffi
• python HelloWindows.py
• Button looks like modern windows style(not win98/xp) because python.exe itself has manifest file resource

HelloSDL3.py

• Python script that uses ctypes for loading sdl3.dll
• and also shows how to fill the fields according to functions return value and parameters
• Finally creates a blank sdl3 window
• python HelloSDL3.py
• sdl3.dll must be placed in Python's one of sys.path

RegisterClass.py

• Python script uses ctypes for filling WNDCLASSA structure
• then passes Address of WNDCLASSA to RegisterClassA
• also shows how to declare a windows structure and how to fill it
• python RegisterClass.py