Ruby  1.9.3p448(2013-06-27revision41675)
Data Structures
Here are the data structures with brief descriptions:
[detail level 12]
 C__sbuf
 C__sFILE
 C__siov
 C__suio
 C_BBuf
 C_FreeNode
 C_Node
 C_NtCmdLineElement
 C_OnigStackType
 C_SHA256_CTX
 C_SHA512_CTX
 C_syck_emitter
 C_syck_emitter_node
 C_syck_file
 C_syck_level
 C_syck_node
 C_syck_parser
 C_syck_str
 C_Win32OLEIDispatch
 Caccept_arg
 Caddrinfo
 Cafd
 CAnchorNode
 Cargf
 Cargf_call_arg
 Cary_sort_data
 Casciicompat_encoding_t
 Casynchronous_arg_t
 Cbackref_name_tag
 Cbig_div_struct
 CBigint
 Cbinwrite_arg
 Cbrace_args
 CBRefNode
 Cbytestring_t
 CC_block
 Ccache_entry
 Ccall_queue
 CCallNode
 CCaseFold_11_Type
 CCaseUnfold_11_Type
 CCaseUnfold_12_Type
 CCaseUnfold_13_Type
 Ccbsubst_info
 CCClassNode
 Ccfunc_data
 CCHAR64LONG16
 Cchdir_data
 Cchild_info
 CChildRecord
 Cchown_args
 Cchunk_arg
 Cclone_method_data
 Ccmd_body_arg
 Ccmdline_options
 CCodePointList2
 CCodePointList3
 CComplexDateData
 Cconnect_arg
 CConsAltNode
 Cconv_method_tbl
 Ccopy_stream_struct
 Ccparse_params
 CCtypeNode
 CDateData
 Cdatum
 CDBM
 Cdbmdata
 Cdefault_encoding
 CDIR
 Cdir_data
 Cdirect
 Cdl_handle
 Cdump_arg
 Cdump_call_arg
 Ceach_obj_args
 Cemitter_xtra
 CEncloseNode
 Cend_proc_data
 Censure_range
 Cenumerator
 Cequal_data
 Ceval_queue
 Cevent_call_args
 Cevloop_params
 Cexec_recursive_params
 CFBufferStruct
 Cfc_result
 Cfiddle_closure
 Cfiddle_generic
 Cfinish_writeconv_arg
 Cforce_finalize_list
 Cforeach_arg
 Cforeach_safe_arg
 Cfrom_utf8_mac_status
 Cgc_list
 Cgc_profile_record
 Cgenerator
 Cgetaddrinfo_arg
 Cgetnameinfo_arg
 Cglob_args
 Cglob_pattern
 Cglobal_variable
 CGroupNumRemap
 Cgzfile
 Chash_foreach_arg
 Cheaps_slot
 Chostent_arg
 CIApplyCaseFoldArg
 Ciconv_env_t
 CIEventSink
 CIEventSinkVtbl
 CINamesArg
 Cinetsock_arg
 Cinput_code
 Cinvoke_info
 Cinvoke_queue
 Cio_internal_read_struct
 Cio_internal_write_struct
 Cioctl_arg
 Cioinfo
 Ciovec
 Ciseq_adjust_data
 Ciseq_catch_table_entry
 Ciseq_compile_data
 Ciseq_compile_data_ensure_node_stack
 Ciseq_compile_data_storage
 Ciseq_inline_cache_entry
 Ciseq_insn_data
 Ciseq_insn_info_entry
 Ciseq_label_data
 Ciseq_link_anchor
 Ciseq_link_element
 Citer_method_arg
 Cjoin_arg
 CJSON_Generator_StateStruct
 CJSON_ParserStruct
 Ckwtable
 Cload_arg
 Cload_file_arg
 Cloaded_feature_searching
 Clocal_vars
 Cmagic_comment
 Cmark_stack
 Cmark_tbl_arg
 Cmarshal_compat_t
 Cmd5_state_s
 CMETHOD
 Cminmax_by_t
 Cminmax_t
 CMinMaxLen
 Cmktime_arg
 Cmsghdr
 CMT
 CmyCPINFOEX
 CNameEntry
 Cnative_thread_data_struct
 Cnew_wrap_arg_t
 Cnkf_buf_t
 Cnkf_encoding
 Cnkf_native_encoding
 Cnkf_state_t
 CNodeBase
 CNodeOptInfo
 Cobj_ivar_tag
 Coledata
 Coleeventdata
 Colemethoddata
 Coleparam
 Coleparamdata
 Coletypedata
 Coletypelibdata
 Colevariabledata
 Colevariantdata
 COnigCaptureTreeNodeStruct
 COnigCaseFoldCodeItem
 COnigCompileInfo
 COnigEncodingTypeST
 COnigErrorInfo
 COnigMatchArg
 COnigMetaCharTableType
 COnigPairCaseFoldCodes
 COnigRepeatRange
 COnigSyntaxType
 COnigToken
 COptAncInfo
 COptEnv
 COptExactInfo
 COptMapInfo
 Cos_each_struct
 Cossl_asn1_info_t
 Cossl_verify_cb_args
 Cpair_t
 Cparser_params
 Cparser_xtra
 Cpipe_list
 Cposix_regmatch_t
 CPosixBracketEntryType
 Cptr_data
 Cpty_info
 CQtfrNode
 CRArray
 Crawmode_arg_t
 Crb_addrinfo_t
 Crb_binding_t
 Crb_block_struct
 Crb_blocking_region_buffer
 Crb_classext_struct
 Crb_compile_option_struct
 Crb_const_entry_struct
 Crb_context_struct
 Crb_control_frame_t
 Crb_data_type_struct
 Crb_deprecated_classext_struct
 Crb_digest_metadata_t
 Crb_econv_elem_t
 Crb_econv_init_by_convpath_t
 Crb_econv_t
 Crb_encoding_entry
 Crb_env_t
 Crb_event_hook_struct
 Crb_exec_arg
 Crb_fiber_struct
 Crb_global_entry
 Crb_global_vm_lock_struct
 Crb_iconv_opt_t
 Crb_io_buffer_t
 Crb_io_t
 Crb_iseq_struct
 Crb_method_attr_struct
 Crb_method_cfunc_struct
 Crb_method_definition_struct
 Crb_method_entry_struct
 Crb_mutex_struct
 Crb_objspace
 Crb_proc_t
 Crb_random_t
 Crb_thread_cond_struct
 Crb_thread_struct
 Crb_transcoder
 Crb_transcoding
 Crb_unblock_callback
 Crb_vm_protect_tag
 Crb_vm_struct
 Crb_vm_tag
 CRBasic
 CRBignum
 CRClass
 CRComplex
 CRData
 Cre_pattern_buffer
 Cre_registers
 CReal
 Crecvfrom_arg
 Creg_named_capture_assign_t
 Crescue_funcall_args
 CRFile
 CRFloat
 CRHash
 CRMatch
 Crmatch
 Crmatch_offset
 CRMD160_CTX
 CRNode
 CRObject
 CRRational
 CRRegexp
 Crsock_send_arg
 CRString
 CRStruct
 CRTypedData
 Cruby_gc_params_t
 Cruby_method_ids_check
 CRVALUE
 Cs_double
 Cs_float
 Cs_int
 Cs_long
 Cs_short
 Cs_voidp
 CScanEnv
 Csearch_path_bfs_t
 Csearch_path_queue_tag
 Cseek_arg
 Cselect_args
 CSHA1_CTX
 Cshift_var
 Csignals
 CSimpleDateData
 Csip_hash
 Csip_interface_st
 Csip_state
 Csip_uint64_t
 Cslicebefore_arg
 Csockaddr_storage
 Csockinet
 Csort_by_data
 Csorted_heaps_slot
 Cst_hash_type
 Cst_str_end_key
 Cst_table
 Cst_table_entry
 Cstack_chunk
 Cstack_node
 CStringIO
 CStrNode
 Cstrscanner
 Csymbols
 Csysopen_struct
 CtagIEVENTSINKOBJ
 Ctcltkip
 Cth_update_param
 Cth_vwait_param
 Cthgroup
 Cthgroup_list_params
 Cthread_call_proc_arg
 Ctime_object
 Ctimespec
 Ctimeval
 Ctimezone
 Ctms
 Ctmx
 Ctmx_funcs
 Ctoken_assoc
 Ctoken_info
 Ctotal_data
 Ctr
 Ctrace_data
 Ctrace_var
 Ctrans_open_t
 Ctranscoder_entry_t
 Ctrap_arg
 Ctype_cclass_key
 Ctypes
 CU
 Cudp_arg
 Cuniname2ctype_pool_t
 Cuniname2ctype_struct
 Cunlinked_method_entry_list_entry
 CUnsetAddr
 CUnsetAddrList
 Cupdate_arg
 Cutimbuf
 Cutime_args
 Cvtable
 Cvtm
 Cwait_data
 Cwgetch_arg
 Cwgetstr_arg
 Cwindata
 Cwrite_arg
 CWSAMSG
 Cyaml_instruction
 Cyielder
 Cyyalloc
 CYYSTYPE
 Czone
 Czstream