# Couldn't find 'jl\_is\_float64' declaration in julia.h

**URL:** https://discourse.julialang.org/t/couldnt-find-jl-is-float64-declaration-in-julia-h/3818
**Category:** Internals & Design
**Tags:** question
**Created:** [May 20, 2017, 10:06am UTC](https://discourse.julialang.org/t/couldnt-find-jl-is-float64-declaration-in-julia-h/3818 "2017-05-20T10:06:18Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![tastelessjolt](https://avatars.discourse-cdn.com/v4/letter/t/f14d63/32.png) [@tastelessjolt](https://discourse.julialang.org/u/tastelessjolt)
#### Post date: [May 20, 2017, 10:06am UTC](https://discourse.julialang.org/t/couldnt-find-jl-is-float64-declaration-in-julia-h/3818/1 "2017-05-20T10:06:18Z")

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Why isn’t there a ‘jl\_is\_float64’ declaration? As a result, I’m not able to use it in Embedding Julia in my C program.  
Is it removed deliberately?  
Thank you.

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### Author: ![nalimilan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nalimilan/32/147_2.png) [@nalimilan](https://discourse.julialang.org/u/nalimilan)
#### Post date: [May 20, 2017, 10:46am UTC](https://discourse.julialang.org/t/couldnt-find-jl-is-float64-declaration-in-julia-h/3818/2 "2017-05-20T10:46:07Z")

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I guess you’re using Julia 0.6? Then [the manual](https://docs.julialang.org/en/latest/manual/embedding.html) says to use `jl_typeis(x, jl_float64_type)` instead.

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### Author: ![tastelessjolt](https://avatars.discourse-cdn.com/v4/letter/t/f14d63/32.png) [@tastelessjolt](https://discourse.julialang.org/u/tastelessjolt)
#### Post date: [May 20, 2017, 6:56pm UTC](https://discourse.julialang.org/t/couldnt-find-jl-is-float64-declaration-in-julia-h/3818/3 "2017-05-20T18:56:06Z")

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Oh, I’m sorry, didn’t check the docs version. Thank you.