autocmd with quickfix window

Question

How can set BufEnter or WinEnter autocmds for entering quickfix window?

I tried

autocmd WinEnter quickfix echo 'winenter'
autocmd BufEnter quickfix echo 'bufenter'

None of them works. I doubt that it is because these two commands needs file name after the event name. Then what is the file pattern for quickfix window?

I have fugitive installed. By filling the quickfix window using Glog, the statusline for the quickfix window shows something like [:git --git-dir=...] [Quickfix List]. Is this the filename of the quickfix buffer which should be used in the pattern of the BufEnter/WinEnter event?

I cannot see anything if I echo @% which should usually show the current bufname.

Answer 1

The parameter for both the WinEnter and BufEnter events are matched against the buffer name, which is empty for the quickfix window:

:echo bufname('')
[no output]

You can still use the buftype variable though:

autocmd WinEnter * if &buftype == 'quickfix' | echo 'winenter' | endif

Answer 2

Just a remark to Martin Tournoij answer.

When you just opened a quickfix buffer/window (and not switched to it yet), the &buftype option is not set yet. You may find another autocommand event useful:

autocmd BufWinEnter quickfix echo 'bufwinenter'