# \`\_dump\_function\` not defined

**URL:** <https://discourse.julialang.org/t/dump-function-not-defined/17012>\
**Category:** Internals & Design\
**Created:** [October 31, 2018, 4:52pm UTC](https://discourse.julialang.org/t/dump-function-not-defined/17012 "2018-10-31T16:52:27Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![oliver](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oliver/32/19264_2.png) [@oliver](https://discourse.julialang.org/u/oliver)\
**Post date:** [October 31, 2018, 4:52pm UTC](https://discourse.julialang.org/t/dump-function-not-defined/17012/1 "2018-10-31T16:52:27Z")

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I’m looking at a section of [`v.1.1-dev`](https://docs.julialang.org/en/v1.1-dev/devdocs/llvm/) of the documentation which provides an exampls

`It is also possible to dump an LLVM IR module for just one Julia function, using:`

```julia
f, T = +, Tuple{Int,Int} # Substitute your function of interest here
optimize = false
open("plus.ll", "w") do f
    println(f, Base._dump_function(f, T, false, false, false, true, :att, optimize))
end

```

However I get

```julia
ERROR: UndefVarError: _dump_function not defined
(...)

```

I tried adding and using `LLVM` without success.

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<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [October 31, 2018, 8:17pm UTC](https://discourse.julialang.org/t/dump-function-not-defined/17012/2 "2018-10-31T20:17:58Z")

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Which Julia version are you using? That function only exists on the master branch of Julia, as far as I can tell.

If you’re looking for the docs for 1.0.1, they’re [here](https://docs.julialang.org/en/v1.0.1/) (select 1.0.1 in the dropdown up left in the docs).

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<div class="post-metadata">

**Author:** ![oliver](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oliver/32/19264_2.png) [@oliver](https://discourse.julialang.org/u/oliver)\
**Post date:** [October 31, 2018, 9:48pm UTC](https://discourse.julialang.org/t/dump-function-not-defined/17012/3 "2018-10-31T21:48:29Z")

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I am using 1.0.1, I included the `dev` docs since I thought they might have been different.

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<div class="post-metadata">

**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [October 31, 2018, 10:02pm UTC](https://discourse.julialang.org/t/dump-function-not-defined/17012/4 "2018-10-31T22:02:40Z")

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`dev` docs are for `dev` versions - the functions documented there are not yet available in a regular release.

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<div class="post-metadata">

**Author:** ![oliver](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oliver/32/19264_2.png) [@oliver](https://discourse.julialang.org/u/oliver)\
**Post date:** [October 31, 2018, 10:23pm UTC](https://discourse.julialang.org/t/dump-function-not-defined/17012/5 "2018-10-31T22:23:32Z")

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It’s identical between the two, I included dev references because it may reflect any updates.