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Re: What's the right way to detect libxml2?
From: |
Andy Moreton |
Subject: |
Re: What's the right way to detect libxml2? |
Date: |
Tue, 24 Oct 2017 14:38:33 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.0.90 (windows-nt) |
On Sun 22 Oct 2017, Phillip Lord wrote:
> On Sun, October 22, 2017 2:14 pm, Clément Pit-Claudel wrote:
>> Hi emacs-devel,
>>
>>
>> In Flycheck we use ``libxml-parse-region`` if available, and fall back to
>
>> ``xml-parse-region`` otherwise. We recently realized that our libxml
>> detection code was wrong, however.
>>
>> We used to write ``(if (fboundp 'libxml-parse-region)
>> (libxml-parse-region …) (xml-parse-region …))``, but this isn't
>> sufficient on Windows, where ``fboundp`` succeeds if Emacs was compiled
>> with libxml support, even if the appropriate DLL isn't installed on the
>> user's system.
>>
>> What's the proper way to autodetect libxml? We're thinking of doing this
>> instead::
>>
>>
>> (if (and (fboundp 'libxml-parse-region)
>> (with-temp-buffer
>> (insert "<xml/>")
>> (libxml-parse-region (point-min) (point-max))))
>> (libxml-parse-region …)
>> (xml-parse-region …))
>>
>>
>> Do we have better options?
>
> We need a better option, as it happens. I have the same problem when
> building the windows binary package. I've got no way of testing whether
> libxml (or any of the other DLLs) are present or work.
M-x list-dynamic-libraries shows the loaded DLLs, but you still need to
perform some work that causes the relevant libraries to loaded
beforehand.
For libxml2, try using (shr-render-buffer) on an HTML/XML buffer to get
the library loaded.
For some other libraries there are helpers:
(gnutls-available-p)
(image-type-available-p 'gif)
(image-type-available-p 'imagemagick)
(image-type-available-p 'jpeg)
(image-type-available-p 'png)
(image-type-available-p 'svg)
(image-type-available-p 'tiff)
(image-type-available-p 'xpm)
(lcms2-available-p)
(zlib-available-p)
Adding predicates for the remaining dynamic libraries would be useful.
AndyM
- What's the right way to detect libxml2?, Clément Pit-Claudel, 2017/10/22
- Re: What's the right way to detect libxml2?, Phillip Lord, 2017/10/22
- Re: What's the right way to detect libxml2?,
Andy Moreton <=
- Re: What's the right way to detect libxml2?, Clément Pit-Claudel, 2017/10/24
- Re: What's the right way to detect libxml2?, Andy Moreton, 2017/10/24
- Re: What's the right way to detect libxml2?, Robert Pluim, 2017/10/24
- Re: What's the right way to detect libxml2?, Andy Moreton, 2017/10/24
- Re: What's the right way to detect libxml2?, Robert Pluim, 2017/10/25
- Re: What's the right way to detect libxml2?, Eli Zaretskii, 2017/10/28
- Re: What's the right way to detect libxml2?, Robert Pluim, 2017/10/30
- Re: What's the right way to detect libxml2?, Eli Zaretskii, 2017/10/30
- Re: What's the right way to detect libxml2?, Eli Zaretskii, 2017/10/30
- Re: What's the right way to detect libxml2?, Richard Stallman, 2017/10/24