---
title: SetFallbackUnicodeToText
framework: Core Services
role: symbol
role_heading: Function
platforms: [macOS 10.0+]
path: coreservices/1433614-setfallbackunicodetotext
---

# SetFallbackUnicodeToText

Specifies a fallback handler to be used for convertinga Unicode text segment to another encoding when the Unicode Convertercannot convert the text using the mapping table specified by theUnicode converter object.

## Declaration

```occ
OSStatus SetFallbackUnicodeToText(UnicodeToTextInfo iUnicodeToTextInfo, UnicodeToTextFallbackUPP iFallback, OptionBits iControlFlags, LogicalAddress iInfoPtr);
```

## Parameters

- `iUnicodeToTextInfo`: The Unicode converter object to which the fallback handler is to be associated. You use the function doc://com.apple.documentation/documentation/coreservices/1433522-createunicodetotextinfo or doc://com.apple.documentation/documentation/coreservices/1433550-createunicodetotextinfobyencodin to obtain a Unicode converter object of this type.
- `iFallback`: A universal procedure pointer to the application-defined fallback routine. For a description of the function prototype that your fallback handler must adhere to and how to create your own fallback handler, see doc://com.apple.documentation/documentation/coreservices/unicodetotextfallbackprocptr. You should use the NewUnicodeToTextFallbackProc macro to convert a pointer to your fallback handler into a UnicodeToTextFallbackUPP.
- `iControlFlags`: Control flags that stipulate which fallback handler the Unicode Converter should call—the application-defined fallback handler or the default handler—if a fallback handler is required, and the sequence in which the Unicode Converter should call the fallback handlers if either can be used when the other fails or is unavailable. See doc://com.apple.documentation/documentation/coreservices/1433507-fallback_handler_selectors.
- `iInfoPtr`: A point to a block of memory to be passed to the application-defined fallback handler. The Unicode Converter passes this pointer to the application-defined fallback handler as the last parameter when it calls the fallback handler. Your application can use this memory block to store data required by your fallback handler whenever it is called. This is similar in use to a reference constant (refcon). If you don’t need to use a memory block, specify NULL for this parameter.

## Return Value

Return Value A resultcode. See Result Codes.

## Discussion

Discussion You can define multiple fallback handlers and associate themwith different Unicode converter objects, depending on your requirements.See  UnicodeToTextFallbackProcPtr  fora description of how to create and install an application-definedfallback handler. You can use a fallback handler when one of the Unicode conversionfunctions,  ConvertFromUnicodeToText , ConvertFromUnicodeToTextRun , ConvertFromUnicodeToPString ,and  ConvertFromUnicodeToScriptCodeRun ,cannot convert the text using the mapping table specified by theUnicode converter object passed to the function.

## See Also

### Setting the Fallback Handler

- [SetFallbackUnicodeToTextRun](coreservices/1433644-setfallbackunicodetotextrun.md)