where are definitions of variable/constants shown in PJRC sample C code

[pigtail_parts]

In the sample code snippets at URL "https://www.pjrc.com/teensy/adc.html"
there are variable names that are not defined.
I asssumed there would be a .h file that holds the good stuff.
I have searched in the Teensyduino dir.s under Arduino for strings like "ADCSRA", "ADC_PRESCALER"
but have not found/stumbled onto such a file.

 

[el_supremo]

That page only mentions the "Teensy 2.0 and Teensy++ 1.0 & 2.0" all of which use AtMega-based processors, which is presumably why ADCSRA is only defined in the avr directory tree ...\hardware\teensy\avr\avr\...
ADC_PRESCALER is defined in ...\hardware\teensy\avr\cores\teensy\wiring_private.h

To use ADC later Teensy processors see the ADC examples in the IDE/Teensyduino.

Pete