# Error using ff-c++

**URL:** https://community.freefem.org/t/error-using-ff-c/1812
**Category:** FreeFEM installation
**Created:** [June 15, 2022, 8:04pm UTC](https://community.freefem.org/t/error-using-ff-c/1812 "2022-06-15T20:04:31Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![matthieu.brachet](https://avatars.discourse-cdn.com/v4/letter/m/5f9b8f/32.png) [@matthieu.brachet](https://community.freefem.org/u/matthieu.brachet)
#### Post date: [June 15, 2022, 8:04pm UTC](https://community.freefem.org/t/error-using-ff-c/1812/1 "2022-06-15T20:04:31Z")

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While trying to compile _lapack with ff-c++ lapack.cpp -llapack_ I get the error _erreur PB include freefem++ directory_  
My freefem files compile well until I am not loading lapack. Probably the mistake is stupid but I can’t find a solution.

Someone know what is wrong?

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### Author: ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)
#### Post date: [June 22, 2022, 9:55am UTC](https://community.freefem.org/t/error-using-ff-c/1812/2 "2022-06-22T09:55:05Z")

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Dear user ,

You give not information on the computer, system, version of FreeFEM,  
So it is hard to say something.