BeginIf / EndIf

Encloses directives that will be processed only if a test is true at startup. This is equivalent to httpd 's IfDefined

BeginIf Defined 
    ForceLog "defined"
EndIf

BeginIfNot / EndIfNot

Same as above for false values. This is equivalent to httpd's IfDefined !parameter-name

BeginIfNot Defined test
   ForceLog "not defined"
EndIfNot