:char - Signed 8-bits. A dereferenced :char pointer returns an character.

:unsigned-char - Unsigned 8-bits. A dereferenced :unsigned-char pointer returns an character.

:byte - Signed 8-bits. A dereferenced :byte pointer returns an integer.

:unsigned-byte - Unsigned 8-bits. A dereferenced :unsigned-byte pointer returns an integer.

:short - Signed 16-bits.

:unsigned-short - Unsigned 16-bits.

:int - Signed 32-bits.

:unsigned-int - Unsigned 32-bits.

:long - Signed 32 or 64 bit integer, depending upon the platform.

:unsigned-long - Unsigned 32 or 64 bit integer, depending upon the platform.

:long-long - Signed 64 bits integer for implementations that support this. If implementation does not support this, 'uffi:no-long-long is pushed on the <variable>cl:*features*</variable> list.

:unsigned-long-long - Unsigned 64 bits integer for implementations that support this. If implementation does not support this, 'uffi:no-long-long is pushed on the <variable>cl:*features*</variable> list.

:float - 32-bit floating point.

:double - 64-bit floating point.

:cstring - A NULL terminated string used for passing and returning characters strings with a C function.

:void - The absence of a value. Used to indicate that a function does not return a value.

:pointer-void - Points to a generic object.

* - Used to declare a pointer to an object