Vimscript: How to check if a buffer is modified

Question

Given a buffer number i, I want to check if the buffer has been modified after the last save. How do I do that in vimscript?

I tried to use getbufvar() like the following:

if getbufvar(i, "&modified")
  echo "Modified"
else
  echo "Not Modified"
endif

but this always seems to echo "Modified". What am I doing wrong?

Answer 1

You could work with getbufinfo(). Note that this function always returns a list of dictionaries.

if getbufinfo(i)[0].changed
    echo "Modified"
else
    echo "Not Modified"
endif

Note that this will fail, if the buffer with the number i does not exist.

BTW: If you want to know all changed buffers do:

for buf in getbufinfo({'bufmodified': 1})
    echo buf.bufnr
endfor

If you want to know about the current buffer do:

if getbufinfo('%')[0].changed
    echo "Modified"
else
    echo "Not modified"
endif

See :h getbufinfo for the details.