Re: [PATCH 1/1] vreportf(): avoid buffered write in favor of unbuffered one

> > Also, this is only to help output from us that goes via vreportf() and
> > other codepaths in us that use stdio to write to the standard error
> > stream can still get mixed on Windows (I think the answer is yes,
> > because we wouldn't need fflush() in this patch if we are covering all
> > writes to the standard error stream)?
> 
> Yes, `write()` can get interrupted, so there is still a slight chance of
> interleaving.
> 
> However, with `fprintf()`, apparently the MSVC runtime essentially
> writes and flushes one character at a time, which will make it _much_
> more likely that two competing processes write interleaved messages to
> `stderr`.

> > > -	vsnprintf(msg, sizeof(msg), err, params);
> > > +	size_t off = strlcpy(msg, prefix, sizeof(msg));
> >
> > Like snprintf(3) the strlcpy() and strlcat() functions return the
> > total length of the string they tried to create.  For strlcpy() that
> > means the length of src.
> 
> True (I misread `compat/strlcpy.c` and forgot to consult the
> documentation). This length can be longer than `msg`, of course.

> I `git grep`ed and saw that only very short `prefix`es are hard-coded.
> So that is a hypothetical concern.
> 
> However, Alex also indicated his discomfort with this, so I will change
> the code to account for a `prefix` that is too long (the entire error
> message will be clipped away in that case, which is unfortunate, but to
> be expected).