# How to use Freefem plugin with mmap and semaphore in parallel
**URL:** https://community.freefem.org/t/how-to-use-freefem-plugin-with-mmap-and-semaphore-in-parallel/1911
**Category:** General Discussion
**Created:** [July 25, 2022, 6:33pm UTC](https://community.freefem.org/t/how-to-use-freefem-plugin-with-mmap-and-semaphore-in-parallel/1911 "2022-07-25T18:33:46Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@zcwang6](https://community.freefem.org/u/zcwang6)
#### Post date: [July 25, 2022, 6:33pm UTC](https://community.freefem.org/t/how-to-use-freefem-plugin-with-mmap-and-semaphore-in-parallel/1911/1 "2022-07-25T18:33:46Z")
Dear Freefem team, I was wondering if there is any example shows a way to use mmap and semaphore in freefem in parallel computing? In sequential case, the example on your web page is very useful to me. However, I have a problem to implement it in parallel version. Thank you so much.
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### Author:  [@frederichecht](https://community.freefem.org/u/frederichecht)
#### Post date: [July 26, 2022, 12:30pm UTC](https://community.freefem.org/t/how-to-use-freefem-plugin-with-mmap-and-semaphore-in-parallel/1911/2 "2022-07-26T12:30:52Z")
If you use the code on processor 0 of the mpi , I think all must be ok if the mpi do not use semaphore.
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### Author:  [@zcwang6](https://community.freefem.org/u/zcwang6)
#### Post date: [July 26, 2022, 12:41pm UTC](https://community.freefem.org/t/how-to-use-freefem-plugin-with-mmap-and-semaphore-in-parallel/1911/3 "2022-07-26T12:41:06Z")
let me try it, thank you.