Get return value from function into Visual FoxPro

Hi,
I have a function in SQL Server 2005, this function return 1 value: exist=1 or exist=2
In VFP I have this code:
csql="{call exist_doc( ?tmov, tdoc?)}"
sqlexecute(oApp.Connecthandle,csql)
¿How read return value of variable exist?
Thanks .