# Ann: SWI-Prolog 9.3.10

**URL:** <https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728>\
**Category:** Releases\
**Created:** [August 24, 2024, 1:02pm UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728 "2024-08-24T13:02:00Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [August 24, 2024, 1:02pm UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728/1 "2024-08-24T13:02:00Z")

</div>

Dear SWI-Prolog user,

SWI-Prolog 9.3.10 is ready for download. It is a rather quick release  
that reverts the removed loading of files relative to CWD, restoring  
the old behaviour as deprecated feature. It also fixes a couple of  
serious bugs (affecting few users though). The (xpce) GUI has now  
pretty extensive support for hi-res displays under X11 that should run  
out-of-the-box on configurations that properly report the physical  
layout using the Xrandr extension. Unfortunately that is not always  
the case. Users can overrule the detected DPI in  
`~/.config/swi-prolog/xpce/Defaults` using a line (here telling the  
display is 200DPI). The system uses some heuristics to see whether  
the reported physical size makes sense and sets the dpi to `100` if  
not.

```
display.dpi: 200

Enjoy --- Jan

```

# SWI-Prolog Changelog since version 9.3.9

- DEPRECATED: file search from a source file relative to CWD Searching  
relative to CWD when loading a source file was supported up to  
version 9.3.8. 9.3.9 disabled this, but the implications appear  
too severe. This patch re-enables the old behaviour with a warning.  
The Prolog flag `source_search_working_directory` can be set to  
`false` to disable searching the working directory.

- FIXED: possibly early GC of arguments for call\_cleanup/2 Also affects  
`'$bags':cleanup_bag/2`. The early GC can happen if a signal arrives  
when these predicates are being called and the signal handler calls GC.

- FIXED: use\_module(M, [Pred as Alias]) for meta-predicates

## Package clib

- PORT: Added library(uuid) to WASM version

- ADDED: is\_uuid/1 to test that an atom is a valid UUID

## Package http

- FIXED: http\_open/3 using keep-alive connections When multiple threads  
are connecting to the same host, it may give the same connection to  
multiple threads if a connection was already closed by the peer.

- FIXED: http\_open/3 using Keep-alive This lead to errors if the number  
of cached connections was exceeded (fixed). The library now defines  
the cache parameters as settings, such that applications can change  
them.

## Package pengines

- FIZED: pass SSL Options when destroying pengines

- FIXED: pass SSL options (such as client certificate) to probe.  
Needed to make pengines work in a 2-way SSL setup.

## Package xpce

- PORT: Be more critical on the reported physical dimensions of the  
screen.

- SCALE: Scale stepper/combobox indicator for class `text_item`  
and related.

- SCALE: Properly scale caret in class `text` and `text_item`.

- SCALE: Several dimensions concerning widgets

- SCALE: Make GUI tracer margin scale with bitmaps.

- SCALE: Wrong default for `image.scale` Using `display<-size`  
rather than `display<-dpi`

- ENHANCED: Use Xrandr extension to get DPI resolution of the display  
This seems to provide more reliable results.

- SCALE: Specify default arrow dimensions in mm rather than px.

- FIXED: Compute the GUI tracer stack layout based on the font.

- FIXED: Compute thread-monitor dimensions based on the font

- FIXED: Make sure `image<-size` of built-in images respect the scale

- FIXED: #34 Allow for @display?dpi if there is no display. This notably  
allows for building xpce when there is no DISPLAY.

- MODIFIED: Default scale for fonts and images now depends on DPI This  
implies that one should get a reasonable default if the X server  
provides the right DPI value. If not, setting e.g.

---

<div class="post-metadata">

**Author:** ![kuniaki.mukai](https://avatars.discourse-cdn.com/v4/letter/k/c67d28/32.png) [@kuniaki.mukai](https://swi-prolog.discourse.group/u/kuniaki.mukai)\
**Post date:** [August 27, 2024, 3:33am UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728/2 "2024-08-27T03:33:14Z")

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In version 9.3.10, `spy/1` does not work on macOS 14/ (15 beta). I use mainly ediprolog mode for swi-prolog on Gnu emacs (with Xquarz), have poor knowledge on X and am reluctant  
to go into details on setting X-window-like environment.

```prolog
% swipl --version
SWI-Prolog version 9.3.10 for x86_64-darwin

% swipl    
Welcome to SWI-Prolog (threaded, 64 bits, version 9.3.10-4-g0009ca51f)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.

```

I have found `spy/2` works on M1 macbook pro, but not on imac intel (2020)

```prolog
% ?- spy(...).
%@ [PCE fatal: @display/display: Failed to connect to X-server at `/private/tmp/com.apple.launchd.MzrhT3idUV/org.xquartz:0': malformed DISPLAY address: /private/tmp/com.apple.launchd.MzrhT3idUV/org.xquartz:0
%@ *********************************************************************
%@ * You MUST be running the X11 Windowing environment. If you are, *
%@ * check the setting of your DISPLAY environment variable as well *
%@ * the access rights to your X11 server. See xauth(1) and xhost(1). *
%@ *********************************************************************

<snip>

```

Is there a simple way for `spy/1` to work as before ? Thanks in advance.

---

<div class="post-metadata">

**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [August 27, 2024, 7:18am UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728/3 "2024-08-27T07:18:47Z")

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It means XQuartz, the Mac X11 implementation is not properly working. XQuartz is a bit of a nuisance ☹ It sometimes helps to open it explicitly, at least for me. You have to search there though. Prolog can’t do anything about this.

… except if there is someone willing to write a native MacOS binding for xpce, so we can bypass XQuartz. With good knowledge on how to access MacOS native graphics from C it is not a very big deal. It mostly implies implementing about 150 mostly tiny C functions to do things like “create a Window”, “draw a line”, etc.

---

<div class="post-metadata">

**Author:** ![kuniaki.mukai](https://avatars.discourse-cdn.com/v4/letter/k/c67d28/32.png) [@kuniaki.mukai](https://swi-prolog.discourse.group/u/kuniaki.mukai)\
**Post date:** [August 27, 2024, 10:26am UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728/4 "2024-08-27T10:26:20Z")

</div>

On iMac intel, swipl `spy/2` works with terminal, but not in Emacs.app. No problem with M1 macbook pro and M2 mac mini as usual. I have no idea how to bind swipl with Xquartz in Emacs but I would take it an occasion for me to take time to learn it.

---

<div class="post-metadata">

**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\
**Post date:** [August 27, 2024, 10:47am UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728/5 "2024-08-27T10:47:37Z")

</div>

If it works in one setup, use `?- getenv('DISPLAY', D).` to find the working value. Next, add

```
:- setenv('DISPLAY', <value>).

```

to your `init.pl` file. No guarantees, but it sometimes helps. I’m always a bit unsure where MacOS apps get environment variables. Neither do I know how XQuartz passes the information to apps where the connection can be found.

---

<div class="post-metadata">

**Author:** ![kuniaki.mukai](https://avatars.discourse-cdn.com/v4/letter/k/c67d28/32.png) [@kuniaki.mukai](https://swi-prolog.discourse.group/u/kuniaki.mukai)\
**Post date:** [August 27, 2024, 12:27pm UTC](https://swi-prolog.discourse.group/t/ann-swi-prolog-9-3-10/7728/6 "2024-08-27T12:27:46Z")

</div>

> [@jan](#):
>
> If it works in one setup, use `?- getenv('DISPLAY', D).` to find the working value. Next, add
> 
> ```prolog
> :- setenv('DISPLAY', <value>).
> 
> ```

BINGO ! Thanks for the simple solution.