# sizeof(::Vector{Union{missing,T}}), and hypothetical size

**URL:** <https://discourse.julialang.org/t/sizeof-vector-union-missing-t-and-hypothetical-size/15271>\
**Category:** General Usage\
**Tags:** question\
**Created:** [September 21, 2018, 11:56am UTC](https://discourse.julialang.org/t/sizeof-vector-union-missing-t-and-hypothetical-size/15271 "2018-09-21T11:56:02Z")\
**Posts on this page:** 1\
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**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [September 21, 2018, 1:09pm UTC](https://discourse.julialang.org/t/sizeof-vector-union-missing-t-and-hypothetical-size/15271/3 "2018-09-21T13:09:32Z")

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I thought it used an [`Int8` or similar to keep track of element types](https://discourse.julialang.org/t/small-union-types-present-and-future-looking-for-some-guidelines/6320/2) for each element. So I am wondering if this has changed, or if `sizeof` is missing it.

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