From: Wolfgang Bangerth
+ --enable-compat-blocker=...
: the library offers
+ various functions that maintain compatibility with older
+ versions of deal.II, for example many
+ functions that assume that the mapping between unit and real
+ cell is a (bi-, tri-)linear one. There are respective functions
+ that take a mapping object, and the compatibility functions
+ simply call these with a Q1 mapping object.
+
+ When converting old programs, and also sometimes with new
+ programs, you may want to make sure that these compatibility
+ functions are not called, to ensure that the mapping taken is
+ always the same. In that case, you can configure the library
+ with the flag
+ --enable-compat-blocker=mapping
. After
+ recompilation of the library, each access to these functions is
+ blocked, and an exception is thrown.
+
+ In later versions of the library, other compatibility blockers + will be implemented as well, as we extend the functionality of + the library. +