Q:

Vim Quickfix prefixes double-bar "||" — explain?

I use the Quickfix view in Vim often.
The text in there always has a prefix of || added to it.
So, for instance, when I copy/paste out of that buffer, etc. I get those characters included by default.
Is there a way to disable this?
I haven't had luck finding any documentation or configuration for this...

A:

Quickfix buffer is supposed to be used for parsing specially formatted strings (like compiler messages). This is done with the help of :h 'errorformat' option. And those "bars" are output separators between "filename", "line number" and "the message body".
If you have only "double bars" at the beginning of a line then you either have errorformat set wrong, or you misuse the quickfix buffer.
UPD. If you're interested, "Bars" are hardcoded in Vim's source (src/quickfix.c):
static int
qf_buf_add_line(buf_T *buf, linenr_T lnum, qfline_T *qfp, char_u *dirname)
{
    ...
    if (qfp->qf_module != NULL)
        ...
    if (len < IOSIZE - 1)
        IObuff[len++] = '|';
    if (qfp->qf_lnum > 0)
        ...
    if (len < IOSIZE - 2)
    {
        IObuff[len++] = '|';
        IObuff[len++] = ' ';
    }
    ...
}

