One of the simplest customizations is changing EurekaLog options from the code. ExceptionLog7 unit declares global function CurrentEurekaLogOptions. This function returns TEurekaModuleOptions class (which is declared in EClasses unit), which contains properties corresponding to EurekaLog's options. I.e. almost each property (that you can change in EurekaLog project options dialog) is presented as property in TEurekaModuleOptions class.
For example, you may write a program which is able to work either as Win32 service or as GUI front end - depending on the way it was launched. You probably want to have different bug reports for each of this mode. And Win32 service can't have visual error dialogs. Obviously, this can't be solved by setting options at design-time, since trigger event happens at run-time. So, you setup common options at design time and write such code, which sets the differences:
CurrentEurekaLogOptions is a global function which contains default options for your application in run-time. It affects all exceptions and all threads. Typically, you alter these options at startup (either in initialization section of some unit or in begin/end of .dpr file).
Often there is need to alter option only for some exceptions. EurekaLog provides additional feature for this: events and event hanlders.
Important note: ensure that features specified by your code will be available at run-time. For example, if your application uses MS Classic-styled exception dialog by default and you want to switch to EurekaLog-styled dialog with your code - then be sure to include code for EurekaLog dialog into your application. The same is true for send engines. Hooks and debug information providers are registered on startup and could not be customized at run-time.