Using custom functions (FileMaker Pro Advanced)
To create a custom function:
1.
In FileMaker Pro Advanced, choose File menu > Manage > Custom Functions.
2.
In the Manage Custom Functions dialog box, click New.
3.
In the Edit Custom Function dialog box, for Function Name, type a name for the new function.
Custom function names must be unique and cannot exceed 100 characters.
4.
Build a formula. (For more information, see Working with formulas and functions.)
5.
If the formula requires parameters, for Function Parameters, type the parameter name and click Plus Add button. You can edit or delete a parameter name by selecting it in the list and clicking Edit Edit button or Delete Delete button.
6.
Click where you want an item to appear in the formula box, then perform one of the following actions.
 
To add a
Do this
Reference to a parameter
In the parameters list, double-click a parameter name.
Mathematical or text operator
In the keypad, click an operator.
Comparison or logical operator
For Operators, choose an operator from the list.
Constant value
Type the value.
Function
In the functions list, double-click a function. In the formula box, replace the placeholder parameter with a value or expression.
You can also type parameter names, operators, and functions in the Edit Custom Function dialog box instead of using the lists or keypad.
7.
All accounts is the default option for Availability and allows all users of the current database to see and use the custom function. If you want the custom function to be available only to those with Full Access privileges, select Only accounts assigned full access privileges.
8.
Click OK to close the Edit Custom Function dialog box.
9.
Continue creating custom functions, or click OK to close the Manage Custom Functions dialog box.
To change, duplicate, or delete a custom function:
1.
Choose File menu > Manage > Custom Functions.
2.
In the Manage Custom Functions dialog box:
 
To
Do this
Edit a custom function
For Function Name, select the custom function and click Edit. In the Edit Custom Function dialog box, make your changes, then click OK.
Duplicate a custom function
For Function Name, select the custom function and click Duplicate.
Delete a custom function
For Function Name, select the custom function and click Delete.
3.
In the Manage Custom Functions dialog box, click OK.
To copy a custom function to another FileMaker Pro file:
1.
Choose File menu > Manage > Custom Functions.
2.
In the Manage Custom Functions dialog box, select one or more functions you want to copy.
Tip  You can press Ctrl-click (Windows) or Command-click (OS X) to select non-contiguous functions, or press Shift-click to select contiguous functions.
3.
Press Ctrl+C (Windows) or Command-C (OS X) to copy the functions, then click OK.
Tip  OS X: You can choose File menu > Copy to copy a selected function.
4.
Open a different FileMaker Pro file.
5.
Choose File menu > Manage > Custom Functions.
6.
Press Ctrl+V (Windows) or Command-V (OS X) to paste the functions.
Tip  OS X: You can choose File menu > Paste to paste a selected function.
The custom function you copied appears at the bottom of the list. If FileMaker Pro determines this function is invalid in the context of the target file (for example, a dependent function, field, or calculation is missing from the target file or the function contains an invalid field type reference), the pasted function is enclosed in comment characters (/*<function_definition>*/). For more information, see Custom Function dependency rules (FileMaker Pro Advanced).
7.
Click OK.
Notes
 •
You must have Full Access privileges to the currently active database to create custom functions.
 •
Values, expressions, functions, and parameters can be uppercase or lowercase.
 •
To change the way functions are sorted in the Edit Custom Function dialog box, choose a category from the View list.
 •
The content of a custom function is protected even if it is set to be available to all users with Full Access privileges. To edit or view the custom function content, you must have Full Access privileges and be editing the database in FileMaker Pro Advanced.
 •
When a custom function is deleted, it is no longer available for use. Calculations that were using it will return an error when they attempt to call it. If you have Full Access privileges to a database and are editing a calculation that uses a deleted custom function, the name of the function is replaced with the string <Function Missing>.
 •
If you do not have Full Access privileges and attempt to edit a calculation that uses a custom function restricted to Full Access accounts, you see the string <Private Function> instead of the custom function. You cannot change the calculation as long as the <Private Function> declaration appears in the formula.
 •
If you have previously created custom functions and the names are identical to new FileMaker software functions, the FileMaker functions will override your custom functions. Verify your custom function names against the FileMaker functions, and change your custom function names if needed.
 •
The characters $ and } can no longer be used in a custom function name or a parameter name. If you used these characters in custom function or parameter names in FileMaker Developer, you must rename them in FileMaker Pro Advanced.
 •
You can’t use a script to copy and paste or import custom functions.
Related topics 
About custom functions (FileMaker Pro Advanced)
Importing custom functions (FileMaker Pro Advanced)
Functions reference (category list)
Functions reference (alphabetical list)
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