| _ll_node | Linked list node |
| array_list | Array list struct |
| autoload_t | A structure representing the autoload state for a specific variable, e.g |
| block | Block_t represents a block of commands |
| block_lookup_entry | Datastructure to describe a block type, like while blocks, command substitution blocks, etc |
| buffer | Buffer for concatenating arbitrary data |
| builtin_data | Datastructure to describe a builtin |
| comp_t | Data structure describing one or a group of related completions |
| complete_entry | Struct describing a command completion |
| complete_entry_opt | Struct describing a completion option entry |
| connection | This struct represents a connection between a universal variable server/client |
| drand48_data | Datastructure for the lrand48_r fallback implementation |
| dyn_queue | Data structure for an automatically resizing dynamically allocated queue, |
| env_node | Struct representing one level in the function variable stack |
| event_block | Event_block_t represents a block on events of the specified type |
| event_t | The structure which represents an event |
| function_data | Structure describing a function |
| function_internal_data_t | Struct describing a function |
| halloc | The main datastructure for a main halloc context |
| hash_struct_t | Internal struct used by hash_table_t |
| hash_table | Data structure for the hash table implementaion |
| history_mode_t | A struct representiong a history list |
| input_mapping_t | Struct representing a keybinding |
| io_data | Represents an FD redirection |
| item_t | This struct represents a history item |
| job | A struct represeting a job |
| line_t | A struct representing a single line of a screen |
| lookup_entry | Struct describing an entry for the lookup table used to convert between signal names and signal ids, etc |
| message_t | A struct representing a message to be sent between client and server |
| priority_queue | Data structure for an automatically resizing dynamically allocated priority queue |
| process | A structure representing a single fish process |
| profile_element_t | Struct used to keep track of profiling data for a command |
| reader_data | A struct describing the state of the interactive reader |
| resource_t | Struct describing a resource limit |
| screen_t | The struct representing the current and desired screen contents |
| signal_list_t | This struct contains a list of generated signals waiting to be dispatched |
| terminfo_mapping_t | A struct representing the mapping from a terminfo key name to a terminfo character sequence |
| tokenizer | The tokenizer struct |
| var_entry | A variable entry |
| var_uni_entry | A variable entry |
| wdirent | Wide version of the dirent data structure |
| woption | Describe the long-named options requested by the application |