Q> Как поменять default принтер?

A>

int CALLBACK WinMain( HINSTANCE hInst, HINSTANCE hPrevInst,
LPSTR lpCmdLine, int nShowCmd )
{
/* Get the port & device settings for the specified printer */
char szDeviceString[260];

/* First (and only) parameter is the printer name */
lstrcpy( szDeviceString, __argv[1] );
const int Pos = lstrlen( szDeviceString );

/* Append a ',' */
szDeviceString[ Pos ] = ',';

GetProfileString( "Devices", __argv[1], "",
&szDeviceString[Pos+1],
sizeof( szDeviceString ) - (Pos+1) );

/* Have we got the printer? */
if ( szDeviceString[Pos+1] != '\0' )
{
/* Set the default printer */
WriteProfileString( "windows", "device", szDeviceString );

SendMessageTimeout( HWND_BROADCAST, WM_SETTINGCHANGE, 0L,
(LPARAM)(LPCTSTR)"windows", SMTO_NORMAL,
1000, NULL );
}
else
{
MessageBox( NULL, "Printer not found",
"Set Default Printer Utility",
MB_OK | MB_ICONERROR );
}

return 0;
}

References and samples:

Knowledge Base Article Q135387: "How to Get and Set the Default Printer in
Windows"

Knowledge Base Article Q140560 "How to Set the Default Printer Programmatically
in Windows 95"