# V0.7: "first argument not a pointer or valid constant expression" in ccall

**URL:** <https://discourse.julialang.org/t/v0-7-first-argument-not-a-pointer-or-valid-constant-expression-in-ccall/11502>\
**Category:** General Usage\
**Created:** [June 7, 2018, 1:11pm UTC](https://discourse.julialang.org/t/v0-7-first-argument-not-a-pointer-or-valid-constant-expression-in-ccall/11502 "2018-06-07T13:11:40Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jonathanBieler](https://avatars.discourse-cdn.com/v4/letter/j/82dd89/32.png) [@jonathanBieler](https://discourse.julialang.org/u/jonathanBieler)\
**Post date:** [June 7, 2018, 1:11pm UTC](https://discourse.julialang.org/t/v0-7-first-argument-not-a-pointer-or-valid-constant-expression-in-ccall/11502/1 "2018-06-07T13:11:41Z")

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Is this a bug or a feature ?

```julia
module B
    using Cairo

    test() = ccall((:cairo_version_string,Cairo._jl_libcairo),Cstring,()) 
end

julia> B.test()
ERROR: TypeError: in test, in ccall: first argument not a pointer or valid constant expression, expected Ptr, got Tuple{Symbol,String}

```

Which is a bit werid since both Cairo and \_jl\_libcairo are const (but Cairo.\_jl\_libcairo isn’t ?)

Anyway doing `import Cairo._jl_libcairo` seems to fix the issue.

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**Author:** ![jeff.bezanson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jeff.bezanson/32/48_2.png) [@jeff.bezanson](https://discourse.julialang.org/u/jeff.bezanson)\
**Post date:** [June 7, 2018, 3:08pm UTC](https://discourse.julialang.org/t/v0-7-first-argument-not-a-pointer-or-valid-constant-expression-in-ccall/11502/2 "2018-06-07T15:08:33Z")

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Works in 0.6; this seems to be a regression on master.

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<div class="post-metadata">

**Author:** ![jonathanBieler](https://avatars.discourse-cdn.com/v4/letter/j/82dd89/32.png) [@jonathanBieler](https://discourse.julialang.org/u/jonathanBieler)\
**Post date:** [June 7, 2018, 5:14pm UTC](https://discourse.julialang.org/t/v0-7-first-argument-not-a-pointer-or-valid-constant-expression-in-ccall/11502/3 "2018-06-07T17:14:14Z")

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Ok, I’ll open an issue then.