Tstw.asm and .C are test programs that demonstrate using the features
in Letter Box that allow starting a DOS or Windows application from
a DOS application running in Windows Enhanced Mode.

Source code as well as a working .com program are included.

The shareware version of Letter Box does not support using optional
arguments to control the target application. You must have a registered
version in order to do that.


The technical method for doing this is quite simple. Certain registers
are first loaded and then interrupt 2f hex is called. The call results
in code inside Letter Box being invoked and then it notices that the
format code is 3001 hex and it takes over and passes the string to
a call to WINEXEC. The Show Window parameter is set to SW_NORMAL.

More features are possible with this system. Another code number could
be defined to support passing a Show Window parameter of your choice.
Or provide for a way to call a DLL of your design passing data setup
to your specifications. The DLL could do ANYTHING that you would want
to code it to do. 

A routine using LoadModule instead of WinExec could be set up.
Or a SendMessage system could be implemented.
Or a call to MessageBox.