22. Using 3GL Procedures : Passing Records and Arrays Between 4GL and 3GL Routines : Passing Structured Data
 
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Passing Structured Data
Structured data is passed to 3GL as a handle. Reference the handle in the exec 4gl statements whenever you want to indicate the record or array.
The handle is passed as a 4-byte integer. To store a handle passed in from 4GL, use the long data type on most platforms.
Handles passed to a 3GL routine are not valid after a return to 4GL. For this reason, the 3GL routine does not store a handle in a static variable. After control is returned to 4GL, a later call from 4GL to 3GL cannot use the handle stored earlier in the static variable.