Filter Hooks

Library function:

function extern boolean tcbod.dll0001.table.field.exists(
       const string i.table.field )
{
DllUsage
Expl	This function checks if a specified table field exists.
Input	i.table.field: table field code including table, e.g. "ppmmm999.abcd"
Output	n.a.
Return	true  - table field exists.
	false - table field does not exist.
EndDllusage
 
	long   return.value
	long   dummy.position.field.in.row
	long   dummy.size.field
long   dummy.depth.field
	long   dummy.type.field
	long   dummy.flags
	string dummy.domain.name
	string dummy.default.value
 
	return.value = rdi.column(
                     i.table.field,
                     dummy.domain.name,
                     dummy.position.field.in.row,
                     dummy.size.field,
                     dummy.depth.field,
                     dummy.type.field,
                     dummy.flags,
                     dummy.default.value )
	return(return.value = 0)
}

Define in include hook:

#define	PPMMM999_FLD2 "ppmmm999.fld2"
	| define is needed for filter hook, because otherwise the table code is replaced if 
an alias is used

Filter hook

o.hookFilter = "ppmmm999.fld1 >= 0"
if tcbod.dll0001.table.field.exists(PPMMM999_FLD2) then
	| field fld2 may not exist in all feature packs, so we must check this
	o.hookFilter = o.hookFilter & " and ppmmm999.fld2 = tcyesno.no"
endif
return(0)