how to add the std-c library function in e2 studio ?

If you want to use printf you can also do this with semihosting, which is not the fastest method of printing messages.

If you use J-Link, I recommend to print messages via RTT Viewer. Almost all our examples on Github use this method.

@AZ_Renesas, incorrect, you can direct printf where ever you want using the low level write syscall of newlib. It doesn't have to be used with semihosting.

@AZ_Renesas, incorrect, you can direct printf where ever you want using the low level write syscall of newlib. It doesn't have to be used with semihosting.