In a similar M statement:
LOCK +["XX"]A(7):3, "XX"
The destination is a VMS descriptor that receives the value returned from a database function. GT.M has write-only access to the destination.
The database functions which return a value and therefore require specification of a destination are:
GTM$DATA
GTM$GET
GTM$ORDER
GTM$PREVIOUS
GTM$QUERY
GTM$ZSTATUS
The function returns a MUMPS datum which GT.M converts according to the class and data type of the descriptor. A subsequent section a??Data Types and Descriptorsa??, provides the legal combinations of the class and data types of the destination descriptor.
Example:
gtm$get(GTMI$_EXTGBL, &data, &gdir, &gname)
This specifies GTMI$_EXTGBL as the mode, the variable data as the destination, the global directory gdir as key1 and the global name gname as key2.