External functions
Use external functions to access FileMaker Pro plug-ins. Plug-ins add features to FileMaker Pro. For more information, see Setting plug-in preferences.
External functions are only available if FileMaker Pro plug-ins are installed and enabled on your computer. If no FileMaker Pro plug-ins are installed, you see only the generic external function definition in the Specify Calculation dialog box:
External (nameOfFunction; parameter)
Plug-ins written for version 7.0 and later
Each plug-in defines its own functions and parameters. See the documentation that came with the plug-in for each function’s usage.
Plug-ins written for version 6.0 and earlier
These plug-ins are still supported and continue to use the External function to access the plug-in’s functions. The first parameter is the name of the plug-in function to execute and the second is a parameter that is passed to that function. See the documentation that came with the plug-in for each function’s usage.
 
For more information, see Updating plug-ins.
Related topics 
About functions
About formulas
Topics in this section
External