"so long" vs "too long"

[070281achilles]

I just thought about this.
Which is better or correct? What are the meanings of the following sentences?
"What's taking so long?"
"What's taking too long?"
By the way, what is the meaning of the word "taking" here?
Thanks

 

[emsr2d2]

We don't say "What's taking too long?"

 

[070281achilles]

How do I close a thread without posting?

 

[5jj]

Only moderators can close threads permanently. This one can stay open for the moment in case anyone has a follow-up question.

 

[emsr2d2]

In post #2, I said that we don't say "What's taking too long?" I should have said that we don't use it in the same way that we use "What's taking so long?"

"What's taking so long?" is a rough equivalent of "Why is it/are you taking such a long time to do ...?"

If someone suddenly said out of the blue "It's taking too long" and I had no idea what they were talking about, I would reply with "What's taking too long?" because I need them to clarify the meaning of "It" in their statement.