GL Data Types - OpenGL ES 2.0 / GLSL 1.0

GL types are not C types.

GL Type	Minimum Bit Width	Description
boolean	1	Boolean
byte	8	Signed binary integer
ubyte	8	Unsigned binary integer
char	8	Characters making up strings
short	16	Signed 2’s complement binary integer
ushort	16	Unsigned binary integer
int	32	Signed 2’s complement binary integer
uint	32	Unsigned binary integer
fixed	32	Signed 2’s complement 16.16 scaled integer
sizei	32	Non-negative binary integer size
enum	32	Enumerated binary integer value
intptr	ptrbits	Signed 2’s complement binary integer
sizeiptr	ptrbits	Non-negative binary integer size
bitfield	32	Bit field
float	32	Floating-point value
clampf	32	Floating-point value clamped to [0; 1]