# Help Can't execute XPCE?

**URL:** <https://swi-prolog.discourse.group/t/help-cant-execute-xpce/1073>\
**Category:** Help!\
**Created:** [August 15, 2019, 10:33am UTC](https://swi-prolog.discourse.group/t/help-cant-execute-xpce/1073 "2019-08-15T10:33:20Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jeangil](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jeangil/32/4751_2.png) [@jeangil](https://swi-prolog.discourse.group/u/jeangil)\
**Post date:** [August 15, 2019, 10:33am UTC](https://swi-prolog.discourse.group/t/help-cant-execute-xpce/1073/1 "2019-08-15T10:33:20Z")

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Hello, I’m new with Swi-Prolog and XPCE,  
My pb is I failed many times to execute some exemple as graphical window example ( from Swi-Prolog page tutorials),  
SWP gave me many errors as “_Syntax error: Operator expected_” ?  
I noticed that it happens when I used tutorial exemple with “@” prefix operator (?) Inside it.  
I Dont know if I miss something somewhere ?  
Thanks for your help.

Jeangil

Here I put a copy of my screen after execution :

"Welcome to SWI-Prolog (threaded, 64 bits, version 8.0.3)  
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.  
Please run ?- license. for legal details.

For online help and background, visit [http://www.swi-prolog.org](http://www.swi-prolog.org)  
For built-in help, use ?- help(Topic). or ?- apropos(Word).

?- new(X, picture).  
X = @10174570/picture.

?- send(@10174570, open(point(200,200))).  
ERROR: Syntax error: Operator expected  
ERROR: send(  
ERROR: \*\* here \*\*  
ERROR: @10174570, open(point(200,200))) .  
?-

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**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 15, 2019, 10:53am UTC](https://swi-prolog.discourse.group/t/help-cant-execute-xpce/1073/2 "2019-08-15T10:53:17Z")

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Once upon a time XPCE was an unseperable part of SWI-Prolog. Nowadays it is a not so often used library. To get the operators, load `library(pce)`. In a program that means

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

```

Interacttive you can use `?- [library(pce)].` If you start it from the commandline, recent versions can also use `swipl --pce`.

---

<div class="post-metadata">

**Author:** ![jeangil](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jeangil/32/4751_2.png) [@jeangil](https://swi-prolog.discourse.group/u/jeangil)\
**Post date:** [August 15, 2019, 11:42am UTC](https://swi-prolog.discourse.group/t/help-cant-execute-xpce/1073/3 "2019-08-15T11:42:05Z")

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Thanks a lot Jan,  
now it’s working !!

Regards

Jeangil