| Cbboxunion | Structure to represent all types of bounding boxes |
| CBitMatrix | Structure for storing a bit matrix |
| Ccirc_node | |
| CCommonEntry | Structure to represent information about an entry that can be placed to either group without affecting overlap over selected axis ("common entry") |
| CCompareScalarsContext | |
| CConsiderSplitContext | Structure keeping context for the function period_gist_consider_split |
| CDISTPTS | |
| CDISTPTS3D | |
| Cdouble2 | Structure to represent values of the internal type for computing aggregates for temporal number types |
| Cdouble3 | Structure to represent values of the internal type for computing aggregates for 2D temporal point types |
| Cdouble4 | Structure to represent values of the internal type for computing aggregates for 3D temporal point types |
| CElem | Structure to represent elements in the skiplists |
| CGeoAggregateState | Structure storing the SRID and the dimensionality of the temporal point values for aggregation |
| CGEOGRAPHIC_EDGE | Two-point great circle segment from a to b |
| CGEOGRAPHIC_POINT | Point in spherical coordinates on the world |
| Cgridspec_t | Snap-to-grid Support |
| CLiftedFunctionInfo | |
| CMatch | Struct for storing a match |
| CND_BOX_T | N-dimensional box type for calculations, to avoid doing explicit axis conversions from GBOX in all calculations at every step |
| CND_IBOX_T | N-dimensional box index type |
| CND_STATS_T | N-dimensional statistics structure |
| Cnpoint | |
| Cnsegment | |
| CPeriod | Structure to represent periods |
| CPeriodBound | Internal representation of either bound of a period (not what's on disk) |
| CPeriodBounds | Structure keeping the bounds extracted from a period, for use in the function period_gist_double_sorting_split |
| CPeriodBucketState | Struct for storing the state that persists across multiple calls generating the bucket list |
| CPeriodSet | Structure to represent period sets |
| CRangeBucketState | Struct for storing the state that persists across multiple calls generating the bucket list |
| CScalarMCVItem | |
| CSimilarityPathState | Struct for storing the state that persists across multiple calls generating the bucket list |
| CSkipList | Structure to represent skiplists that keep the current state of an aggregation |
| Csort_node | |
| CSplitInterval | Structure to represent a projection of bounding box to an axis |
| CSTBOX | Structure to represent spatiotemporal boxes |
| CSTboxGridState | Struct for storing the state that persists across multiple calls generating a multidimensional grid |
| CTBOX | Structure to represent temporal boxes |
| CTboxGridState | Struct for storing the state that persists across multiple calls generating the multidimensional grid |
| CTemporal | Structure to represent the common structure of temporal values of any temporal subtype |
| CTemporalAnalyzeExtraData | |
| Ctempsubtype_struct | Structure to represent the temporal subtype array |
| Ctemptype_cache_struct | Structure to represent the temporal type cache array |
| CTimeSplitState | Struct for storing the state that persists across multiple calls to output the temporal fragments |
| CTimestampSet | Structure to represent timestamp sets |
| CTInstant | Structure to represent temporal values of instant subtype |
| CTInstantSet | Structure to represent temporal values of instant set subtype |
| CTSequence | Structure to represent temporal values of sequence subtype |
| CTSequenceSet | Structure to represent temporal values of sequence set subtype |
| CValueSplitState | Struct for storing the state that persists across multiple calls to output the temporal fragments |
| CValueTimeSplitState | Struct for storing the state that persists across multiple calls to output the temporal fragments |
| CVECTOR3D | |
| Cwkb_parse_state | Structure used for passing the parse state between the parsing functions |
