Why does creating a cyclic record cause the Target Language Compiler to crash upon exiting while using the Real-Time Workshop 4.1 (R12,1PV1)?

A cyclic record is one which ends up pointing to itself. They only can be constructed manually, as in the following:

 %createrecord x { }         %%create an empty record x

 %createrecord y { }         %%create an empty record y

 %addtorecord x field y      %%add a field to x which points to y

 %addtorecord y field x      %%add a field to y which points to x

At this point, a cyclic record exists, i.e. x.field.field == x. With this code in place, the TLC crashes when it exits.

Answer 1

[MathWorks Support Team]

Cyclic records are problematic because they cause memory leaks in the Target Language Compiler (TLC). The -dr command line option enables the Target Language Compiler to detect at run time when cyclic records are created and to produce a diagnostic message.

Note, since this feature significantly slows TLC performance, it is "off" by default.