# Upgrade to 0.7: Issue with Mmap

**URL:** <https://discourse.julialang.org/t/upgrade-to-0-7-issue-with-mmap/12965>\
**Category:** Internals & Design\
**Created:** [August 6, 2018, 11:39pm UTC](https://discourse.julialang.org/t/upgrade-to-0-7-issue-with-mmap/12965 "2018-08-06T23:39:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![tobias.knopp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tobias.knopp/32/7551_2.png) [@tobias.knopp](https://discourse.julialang.org/u/tobias.knopp)\
**Post date:** [August 6, 2018, 11:39pm UTC](https://discourse.julialang.org/t/upgrade-to-0-7-issue-with-mmap/12965/1 "2018-08-06T23:39:01Z")

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Hi,

I am trying getting my package 0.7 ready an ran into this issue:

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The issue is that Julia arrays need to have a certain alignment, which mmaped arrays cannot provide.

The issue was also raised here: [mmap with arbitrary offsets no more allowed · Issue #28424 · JuliaLang/julia · GitHub](https://github.com/JuliaLang/julia/issues/28424)  
but it got closed without giving an example how to fix the issue. Would be great if someone could help and give a hint how HDF5 can be fixed.

Thanks!

Tobi

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<div class="post-metadata">

**Author:** ![tobias.knopp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tobias.knopp/32/7551_2.png) [@tobias.knopp](https://discourse.julialang.org/u/tobias.knopp)\
**Post date:** [August 7, 2018, 12:09am UTC](https://discourse.julialang.org/t/upgrade-to-0-7-issue-with-mmap/12965/2 "2018-08-07T00:09:48Z")

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Ok, I think the `reinterpret` workaround seems to work. But then the issue should not be fixed in user code (or HDF5) but in `Mmap.mmap`. That function should give us a reinterpreted Array.