WM_WININICHANGE
wParam = 0; /* not used, must be zero */
lParam = (LPARAM) (LPCSTR) pszSection; /* address of string */An application sends the WM_WININICHANGE message to all top-level windows after making a change to the Windows initialization file, WIN.INI. The SystemParametersInfo function sends the WM_WININICHANGE message after an application uses the function to change a setting in the WIN.INI file.
pszSection
Value of lParam. Points to a string that specifies the name of the section that has changed (the string does not include the square brackets that enclose the section name).
An application should return zero if it processes this message.
To send the WM_WININICHANGE message to all top-level windows, an application can use the SendMessage function with the hwnd parameter set to HWND_BROADCAST.
If an application changes many different sections in WIN.INI at the same time, the application should send the WM_WININICHANGE message once with the pszSection parameter set to NULL. Otherwise, an application should send a separate WM_WININICHANGE message for each change it makes to WIN.INI.
If an application receives a WM_WININICHANGE message with the pszSection parameter set to NULL, the application should check all sections in WIN.INI that affect the application.