# Calling a C function from within a Julia program

**URL:** <https://discourse.julialang.org/t/calling-a-c-function-from-within-a-julia-program/63643>\
**Category:** General Usage\
**Tags:** question, ccall, c\
**Created:** [June 27, 2021, 11:43am UTC](https://discourse.julialang.org/t/calling-a-c-function-from-within-a-julia-program/63643 "2021-06-27T11:43:51Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![Gnimuc](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gnimuc/32/2194_2.png) [@Gnimuc](https://discourse.julialang.org/u/Gnimuc)\
**Post date:** [December 4, 2022, 5:55am UTC](https://discourse.julialang.org/t/calling-a-c-function-from-within-a-julia-program/63643/21 "2022-12-04T05:55:27Z")

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Sorry, it should be `Ref(MTKt_Region())`.

---

<div class="post-metadata">

**Author:** ![mmv](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mmv/32/26323_2.png) [@mmv](https://discourse.julialang.org/u/mmv)\
**Post date:** [December 4, 2022, 9:50am UTC](https://discourse.julialang.org/t/calling-a-c-function-from-within-a-julia-program/63643/22 "2022-12-04T09:50:33Z")

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Bingo! The latest version of that chk\_ function is now

```nohighlight
function chk_mtksetregionbypathblockrange()
    misr_path = convert(Int32, 37)
    misr_block1 = convert(Int32, 32)
    misr_block2 = convert(Int32, 40)
    region_ref = Ref(MTKt_Region())
    status = mtksetregionbypathblockrange!(misr_path, misr_block1, misr_block2, region_ref)
    region = region_ref[]
    println("region.lat = ", region.lat)
    println("region.lon = ", region.lon)
    println("region.xlat = ", region.xlat)
    println("region.ylon = ", region.ylon)
    return status
end

```

and the outcome is as follows:

```nohighlight
julia> Revise.retry()

julia> using MISRToolkit

julia> status = chk_mtksetregionbypathblockrange()
region.lat = 67.28628518822661
region.lon = -95.22204196033839
region.xlat = 633462.5
region.ylon = 307862.5
MTK_SUCCESS::MTKt_status = 0x00000000

julia> 

```

which exactly matches the documentation of that toolkit. Thanks a lot indeed!

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