# WixToolset.WixStandardBootstrapperApplicationFunctionApi WixToolset.WixStandardBootstrapperApplicationFunctionApi contains the SDK for building **BAFunctions** extensions for WixStdBA, the WiX Standard Bootstrapper Application for Burn bootstrapper bundles. BAFunctions are native-code DLLs (typically written in C++) that let you supplement the behavior of WixStdBA, rather than writing an entirely new BA to tweak existing BA behavior. ## Sources https://github.com/wixtoolset/wix/tree/HEAD/src/ext/Bal/wixstdfn ## Samples https://github.com/wixtoolset/wix/tree/HEAD/src/ext/Bal/Samples/bafunctions