char ........... Builtin basic type unsigned char .. Builtin basic type short .......... Builtin basic type unsigned short . Builtin basic type int ............ Builtin basic type unsigned int ... Builtin basic type long ........... Builtin basic type unsigned long .. Builtin basic type float .......... Builtin basic type double ......... Builtin basic type void ........... Builtin basic type bool ........... Builtin basic type Char_t ......... Signed Character 1 byte (char) Int_t .......... Signed integer 4 bytes (int) Bool_t ......... Boolean (0=false, 1=true) (bool) Version_t ...... Class version identifier (short) Double_t ....... Float 8 bytes (double) Option_t ....... Option string (const char) Real_t ......... TVector and TMatrix element type (float) Seek_t ......... File pointer (int) ULong_t ........ Unsigned long integer 4 bytes (unsigned long) Float_t ........ Float 4 bytes (float) Stat_t ......... Statistics type (double) UInt_t ......... Unsigned integer 4 bytes (unsigned int) Text_t ......... General string (char) Axis_t ......... Axis values type (double) Style_t ........ Style number (short) Marker_t ....... Marker number (short) Color_t ........ Color number (short) Short_t ........ Signed Short integer 2 bytes (short) Long_t ......... Signed long integer 4 bytes (long) UChar_t ........ Unsigned Character 1 byte (unsigned char) VoidFuncPtr_t .. pointer to void function Handle_t ....... Generic resource handle Display_t ...... Display handle Visual_t ....... Visual handle Window_t ....... Window handle Pixmap_t ....... Pixmap handle Drawable_t ..... Drawable handle Region_t ....... Region handle Colormap_t ..... Colormap handle Cursor_t ....... Cursor handle FontH_t ........ Font handle (as opposed to Font_t which is an index) KeySym_t ....... Key symbol handle Atom_t ......... WM token GContext_t ..... Graphics context handle FontStruct_t ... Pointer to font structure Mask_t ......... Structure mask type Time_t ......... Event time UShort_t ....... Unsigned Short integer 2 bytes (unsigned short) Ssiz_t ......... String size (int) SCoord_t ....... Screen coordinates (short) Font_t ......... Font number (short) Width_t ........ Line width (short) Size_t ......... Attribute size (float)