Using printf with \r does not print anything

[RandomInternetGuy]

You're welcome.

I totally believe that the default behavior changed. Honestly, I'm more surprised that the old behavior was as it was until approximately now. (In computer science years)

The older behavior really is more common in super tiny systems where a difference of a few k can totally blow your ram budget or when there's low cost - and no flow control - to the path that shoves a character straight into the uart.

Where system calls. Are expensive or you may be producing characters way faster then the receiver can eat them, or when there is high overhead to setting up a transmit (consider dma.that requires word alignement, starting that dma, locking those pages down from being paged out or overwritten until you receive an interrupt, etc. You can probably do 10 characters or 1000.at the same cost, but it's like starting a 747 engine to move one meter. You really want to do a full plane/buffer's worth of cargo once you start that 747.


Glad you got to the bottom of this. Hopefully this thread can help others., Too. It seems unlikely you'd be the only one nailed by this.