I don't leave open connections for more than the time that I require, however, you could set an error handler to capture the "Connection Handle Invalid" error and run a simple query with SPT using your connection that returns a known record and test the return value of SQLEXEC() and the results of the error handler like:

m.lcOnError = on("error")
m.llhadSQLerror = .f.
on error m.llhadSQLerror = .t.
*!* do SQLEXEC 
if m.llhadSQLerror
*!* Error occurred with SQLEXEC()
endif
on error &lcOnError

>connection is made at start of application. But status of connection needs to be tested before each sqlexec(). App could be running for along time and lose connection. Then SQLexec() could fail. The idea is to test the connection before issuing SQLexex()
>
>Thank You Miles