# @/1 not defined in 10.0.0?

**URL:** <https://swi-prolog.discourse.group/t/1-not-defined-in-10-0-0/9415>\
**Category:** Help!\
**Created:** [December 5, 2025, 9:15pm UTC](https://swi-prolog.discourse.group/t/1-not-defined-in-10-0-0/9415 "2025-12-05T21:15:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![hnbeck](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/hnbeck/32/3149_2.png) [@hnbeck](https://swi-prolog.discourse.group/u/hnbeck)\
**Post date:** [December 5, 2025, 9:15pm UTC](https://swi-prolog.discourse.group/t/1-not-defined-in-10-0-0/9415/1 "2025-12-05T21:15:15Z")

</div>

Thanks for this big work leading to 10.0.0. I’m using at MacOS (latest release)

It seems that the XPCE reference operator @/1 is not defined, because such like  
`send(@12345, open(point(100,100))). `  
fails with syntax error (“Operator expected”) ?

Is this possible? How to get the XPCE Manual with the bunch of examples back (was in earlier version in the help menu)? Sorry in advance if I missed something in the release notes or readmes

Best

Hans

```prolog
% your code here

```

---

<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:** [December 6, 2025, 9:16am UTC](https://swi-prolog.discourse.group/t/1-not-defined-in-10-0-0/9415/2 "2025-12-06T09:16:43Z")

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To get the operator, run

```
?- use_module(library(pce)).

```

Long time ago this was sort of default … The PDF manuals are at [Index of /download/xpce/doc/prolog](https://www.swi-prolog.org/download/xpce/doc/prolog/) The userguide is re-generated and some sections have been updated. Documentation of xpce is still hard to find and outdated ☹ I think I linked the userguide from somewhere, but I forgot where ☹