What file defines ITM_RxBuffer?

[csong.1]

I'm building my application which includes the CMSIS core_cm4.h file and get an `undefined reference to `ITM_RxBuffer'` message. What file actually defines this variable?

[Tesla DeLorean]

You're own..

[Tesla DeLorean]

volatile int32_t ITM_RxBuffer;

https://community.st.com/s/question/0D50X00009Xka2tSAB/itmreceivechar-void-gives-undefined

https://community.arm.com/support-forums/f/keil-forum/33000/use-itm-how-is-the-input-char-saved-into-itm_rxbuffer

https://www.keil.com/pack/doc/CMSIS/Core/html/group__ITM__Debug__gr.html