Caché ObjectScript Reference - InterSystems Documentation

System and Other Functions$ZF(-3) can load only one DLL. Loading a DLL unloads the previous DLL. You can alsoexplicitly unload the currently loaded DLL, which would result in no currently-loaded DLL.(However, note that $ZF(-3) loads and unloads do not affect $ZF(-4) loads and unloads, asdescribed below.)The DLL name specified can be a full pathname, or a partial pathname. If a partial pathname,Caché canonicizes it to the current directory. Generally, DLLs are stored in the binary directory(“bindir”). To locate the binary directory, call the $SYSTEM.Util.BinaryDirectory() method.For further details, refer to the %SYSTEM.Util class in the Caché Class Reference.NotesDynamic-Link LibrariesA DLL is a binary library that contains routines that can be loaded and called at runtime.When a DLL is loaded, Caché finds a function named GetZFTable() within it. IfGetZFTable() is present, it returns a pointer to a table of the functions located in the DLL.Using this table, $ZF(-3) calls the specified function from the DLL.$ZF(-3) and $ZF(-4)Calls to $ZF(-3) can only load one DLL at a time; loading a DLL unloads the previous DLL.To load multiple DLLs concurrently, use $ZF(-4). Loading or unloading a DLL using $ZF(-3)has no effect on DLLs loaded using $ZF(-4).See Also• $ZF(-4) function• $ZF(-5) function• Calling Out of Caché in Using Caché ObjectScript.538 Caché ObjectScript Reference