I mean the files like iox128a1.h
The symbol GPIO can't be used because GPIO_t is not defined.
It could be that nobody in their right mind would use that symbol, but I tried to use it. :)
It is also an official symbol in the Xmega A manual.
The following code is from iox128a1.h
/* ========================================================================== IO Module Instances. Mapped to memory. ========================================================================== */ #define GPIO (*(GPIO_t *) 0x0000) /* General Purpose IO Registers */