Consider the following 'errorformat' configuration:

set errorformat=%f:%l:\ %m

And the following message:

%Warning-ASSIGNDLY: test.v:1: Unsupported: Ignoring delay.

While I expected that this message would not match, for some reason, after running :make Vim is identifying this as a valid error message with the file name %Warning-ASSIGNDLY: test.v. My 'isfname' is with its default value (@,48-57,/,.,-,_,+,,,#,$,%,~), so I really don't understand how Vim is able to match a white space in the file name.

Any ideas?

2 Answers 2


As Tumbler41 notes, isfname has to be turned on:

If "%f" is followed by a '%' or a backslash, it will look for a sequence of 'isfname' characters.

I had no luck inserting a % (%: is an invalid format), but I succeeded with a backslash. This requires a second backslash to escape the first.

:set efm=%f\\:%l:\ %

Then set efm shows the single backslash:

errorformat=%f\:%l: %m 
  • 1
    The % following %f needs to be a part of the actual error format, so e.g. you can do set efm=%f%*[:]%l:%m. Apr 12, 2019 at 9:48

Disclaimer: I have never used errorformat before.

Edit: Deleted pointless stuff that was a mis-understanding of the question.

One other note. Earlier in the help doc it states:

If "%f" is followed by a '%' or a backslash, it will look for a sequence of 'isfname' characters.

Since yours doesn't, maybe that's why it can match a space?

As @JigglyNaga pointed out in the comments, make sure you use two back backslashes as without it set will try to escape the next character.

This is just my (non-expert) take on it. Hope it sparks something for you.

  • I had not tried appending the '%' or '\' before, but I just tried and it didn't help. I will also update my question explaining that I don't want to match this error message.
    – Vitor
    Jun 3, 2016 at 13:52
  • Ah, I see. Sorry about the mis-understanding.
    – Tumbler41
    Jun 3, 2016 at 13:59
  • Don't worry about that, thanks a lot for trying to help me!
    – Vitor
    Jun 3, 2016 at 13:59
  • 1
    @Vitor did you try appending two backslashes - one to escape the other from set?
    – JigglyNaga
    Jun 3, 2016 at 15:27
  • No I did not. And that does appear to work! :) Could you make it an answer, please?
    – Vitor
    Jun 3, 2016 at 16:13

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