>Hi,
>
>Is it correct that Shellexecute(), when fails, returns the value less than 32?

Yes, you can check it at https://docs.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-shellexecutea and http://www.oehive.org/node/528

>I have the following code and want to be sure it is correct.
>
>

>lnResult =Shellexecute(0, tcCommand, tcFileName, tcParameter,tcDirectory,tnShowCommand)
>
>IF lnResult < 32
>	DO CASE
>	CASE lnResult=2
>		cErrorMessage = "Invalid association or URL."
>	CASE lnResult=31
>		cErrorMessage = "No association."
>	CASE lnResult=29
>		cErrorMessage = "Can't start application."
>	CASE lnResult=30
>		cErrorMessage = "Application already open."
>	OTHERWISE
>		cErrorMessage = "No error information"
>	ENDCASE
>ENDIF	
>

>
>TIA