| CCALLINFO | Call information |
| CIREP | IREP Internal REPresentation |
| CIREP_CATCH_HANDLER | IREP Catch Handler |
| CMEMORY_POOL | |
| CMRBC_ALLOC_PROF | For memory allocation profiling functions. if you use this, define MRBC_USE_ALLOC_PROF pre-processor macro |
| CMRBC_ALLOC_STATISTICS | Return value structure for mrbc_alloc_statistics function |
| CMRBC_DEFINE_METHOD_LIST | For mrbc_define_method_list function |
| CRBasic | Base class for some objects |
| CRArray | Array object |
| CRException | Exception object |
| CRHash | Hash object |
| CRInstance | Instance object |
| CRProc | Proc object |
| CRRange | Range object |
| CRString | String object |
| CRClass | Class object |
| CRBuiltinClass | Built-in class object |
| CRBuiltinNoMethodClass | Built-in No method class object |
| CRHashIterator | Define Hash iterator |
| CRKeyValue | Key-Value data |
| CRKeyValueHandle | Key-Value handle |
| CRKeyValueIterator | Key-Value iterator |
| CRMethod | Method management structure |
| CRMutex | Mutex |
| CRObject | Value object |
| CRPrintf | Printf tiny (mruby/c) version data container |
| CRPrintfFormat | Printf tiny (mruby/c) version format container |
| CRTcb | Task control block |
| CSYM_INDEX | |
| Ctr_pattern | |
| CVM | Virtual Machine |