How to disable IME for a particular window
In the East Asian versions of Windows 95 and Windows NT 4.0, applications can call ImmAssociateContext() to disable IME for a certain window. Windows 95 and Windows 4.0 now have a new East Asian Common API Specification that enables this to would work for the Chinese, Japanese, and Korean versions of Windows 95 and Windows NT 4.0.
To disable IME for a certain window, an application can call ImmAssociateContext() API as shown below:
hIMC = ImmAssociateContext(hWnd, NULL);
// It makes IME disable for hWnd window.
// Then you can do whatever you want without IME.
// If you want to enable IME again,
// then you can use the previous stored IME
// context(hIMC) to restore IME.
This method will not work on Windows 3.1 and Windows NT 3.5. You can use WinnlsEnableIME()for these systems, but this function will enable/disable the whole system IME, not just for a specific window.
The reason ImmAssociateContext() does not work on Windows NT 3.51 is that when Microsoft was developing new IMM functions, Windows NT 3.51 was already released with old functionality. Windows NT 3.5 and 3.51 still use Windows 3.1 style IME API like WinnlsEnableIME and SendIMEMessageEx. But, Windows NT 4.0 adapted Windows 95's IME API so that Windows NT 4.0 has the same set of IME API with Windows 95.