(testString.c_str()));
jl_value_t *jtest = jl_call2(wstr2jl, jl_box_voidpointer(my_ptr1), jl_box_uint64(testString.size()));
```
but the `println("2")` has not happened. How to get a correct pointer `const wchar_t *` to Julia?
---
### Author:  [@barche](https://discourse.julialang.org/u/barche)
#### Post date: [April 20, 2017, 4:31pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/10 "2017-04-20T16:31:17Z")
The `unsafe_wrap` function should take 3 arguments, the first being `Array` in this case:
```julia
unsafe_wrap(Array,Ptr{Cwchar_t}(wptr), len)
```
Inspired by this thread, I’m also attempting to add wstring support to [CxxWrap.jl](https://github.com/JuliaInterop/CxxWrap.jl), though it fails on Windows right now. The conversion functions that get called are here:
[https://github.com/JuliaInterop/CxxWrap.jl/blob/master/src/CxxWrap.jl#L405-L406](https://github.com/JuliaInterop/CxxWrap.jl/blob/master/src/CxxWrap.jl#L405-L406)
edit: Actually, it only fails on MSVC, not on MinGW. The failing string compare is here:
[https://ci.appveyor.com/project/barche/cxxwrap-jl/build/1.0.164/job/xmitpqjk6s1ne63v#L1278](https://ci.appveyor.com/project/barche/cxxwrap-jl/build/1.0.164/job/xmitpqjk6s1ne63v#L1278)
No idea why this fails…
---
### Author:  [@Martin\_Florek](https://discourse.julialang.org/u/Martin_Florek)
#### Post date: [April 21, 2017, 6:39am UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/11 "2017-04-21T06:39:47Z")
Thanks @barche. This is Julia part, but how does your part look in c ++ ? i.e. How do you get the `wchar_t` pointer to Julie? If using a generic function ` jl_box_voidpointer()`, then I must probably cast type `Ptr{Void}` to type `Ptr{Cwchar_t}`!?
Correct me if I’m wrong. Thank you very much for taking time for me.
With add `Array` to `unsafe_wrap` this get to `println(2)` 🙂 (Windows 8.1), now just check.
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [April 21, 2017, 1:29pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/12 "2017-04-21T13:29:38Z")
> [@Martin\_Florek](#):
>
> hen I must probably cast type Ptr{Void} to type Ptr{Cwchar\_t}
You do this in the Julia code, as I showed in my example. (I forgot to add the `Array` first argument, as @barche pointed out, and @yuyichao pointed out that you need to root the pointer). Then you call the Julia code from C++. The point, as I’ve been trying to emphasize, is to do as little as possible in C++; write all the glue in Julia.
---
### Author:  [@Martin\_Florek](https://discourse.julialang.org/u/Martin_Florek)
#### Post date: [April 21, 2017, 1:47pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/13 "2017-04-21T13:47:23Z")
Thanks from C++ to Julia it works perfectly and how I get unicode back (in reverse)? From Julia to C++. I have got
```julia
jl_value_t *jl2wstr = jl_eval_string("function jl2wstr() s = \"a_šČô_φ_привет_일보\"; out = transcode(Cwchar_t, s); println(out); out end");
jl_array_t *jl2wstrOut = (jl_array_t*)jl_call0(jl2wstr);
if (jl2wstrOut)
{
wchar_t* xData2 = (wchar_t*)jl_array_data(jl2wstrOut);
f << xData2;
printf("\noutStr = [");
for (size_t i = 0; i < jl_array_len(jl2wstrOut); ++i)
printf("%X ", xData2[i]);
printf("]\n");
}
```
But conversion is not good. I get
`UInt16[0x0061,0x005f,0x009a,0x003f,0xdb37,0xdf9f,0x003f,0x003f,0x003f,0x003f,0x003f,0x003f,0x005f,0x003f,0x003f`
Instead of this
`UInt16[0x0061,0x005f,0x0161,0x010c,0x00f4,0x005f,0x03c6,0x005f,0x043f,0x0440,0x0438,0x0432,0x0435,0x0442,0x005f,0xc77c,0xbcf4]`
---
### Author:  [@barche](https://discourse.julialang.org/u/barche)
#### Post date: [April 21, 2017, 2:49pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/14 "2017-04-21T14:49:26Z")
> [@Martin\_Florek](#):
>
> How do you get the wchar\_t pointer to Julie?
I use `jl_new_bits` to box the pointer in the correct type:
```C
jl_value_t* wchar_dt = jl_get_global(jl_base_module, jl_symbol("Cwchar_t"));
jl_value_t* ptr_dt = jl_apply_type((jl_value_t*)jl_pointer_type, jl_svec1(wchar_dt));
jl_value_t* ptr = jl_new_bits(ptr_dt, (void*)&x); // Boxed Ptr{Cwchar_t} to pass to Julia, x is the C pointer
```
This is pieced together a bit from different places around CxxWrap.jl, so not tested in the form above (and is missing GC rooting, and is v0.5-only). The objective is also different, since this code is used to make wrapping C++ functions returning or consuming std::wstrings, so if you’re using the embedding interface directly I fully support @stevengj 's advice to do as much as possible in Julia (obviously way simpler, too).
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [April 21, 2017, 6:27pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/15 "2017-04-21T18:27:24Z")
> [@Martin\_Florek](#):
>
> `jl_eval_string("function jl2wstr() s = \"a_šČô_φ_привет_일보\";`
The problem is probably that you are entering this string in C++, not in Julia. i.e. the argument to `jl_eval_string` is a C++ string… how is that encoded by your compiler? (The same Julia code works fine for me in the REPL, so I think the problem is just the encoding of the string by your C++ compiler.)
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [April 21, 2017, 6:36pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/16 "2017-04-21T18:36:15Z")
> [@stevengj](#):
>
> `jl_eval_string("...")`
If your compiler supports C++11, you should do `jl_eval_string(u8"...")` so that the Julia code is UTF8-encoded.
---
### Author:  [@barche](https://discourse.julialang.org/u/barche)
#### Post date: [April 23, 2017, 9:29pm UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/17 "2017-04-23T21:29:57Z")
Not sure if it’s related, but for CxxWrap I had to change the encoding of the C++ source file from UTF-8 to UTF-8-BOM for MSVC to do the right thing.
---
### Author:  [@Martin\_Florek](https://discourse.julialang.org/u/Martin_Florek)
#### Post date: [April 24, 2017, 7:58am UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/18 "2017-04-24T07:58:16Z")
I use in MSVC (File \>\>Advanced Save options… \>\> Unicode (UTF-8 without signature)) for correct showing.
But I still do not know how to interpret pointer to `Array{Cwchar_t}` **from Julia back to C++**.??
Can not I use jl\_unbox\_voidpointer()?
Is this the right way?
`jl_array_t *jl2wstrOut = (jl_array_t*)jl_call0(jl2wstr);`
`wchar_t* xData2 = (wchar_t*)jl_array_data(jl2wstrOut);`
---
### Author:  [@barche](https://discourse.julialang.org/u/barche)
#### Post date: [April 24, 2017, 8:58am UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/19 "2017-04-24T08:58:49Z")
> [@Martin\_Florek](#):
>
> Is this the right way?
> jl\_array\_t _jl2wstrOut = (jl\_array\_t_)jl\_call0(jl2wstr);
> wchar\_t\* xData2 = (wchar\_t\*)jl\_array\_data(jl2wstrOut);
That’s basically what I’m doing too, does it give an error?
---
### Author:  [@Martin\_Florek](https://discourse.julialang.org/u/Martin_Florek)
#### Post date: [April 26, 2017, 7:32am UTC](https://discourse.julialang.org/t/unicode-string-from-c-to-julia-and-vice-versa/3272/20 "2017-04-26T07:32:53Z")
@barche If I assign the pointer instead of X, the program fail. See the code.
```julia
jl_value_t* wchar_dt = jl_get_global(jl_base_module, jl_symbol("Cwchar_t"));
jl_value_t* ptr_dt = jl_apply_type((jl_value_t*)jl_pointer_type, jl_svec1(wchar_dt));
//jl_value_t* ptr = jl_new_bits(ptr_dt, (void*)&testString); //pointer to std::basic_string,std::allocator > *
const wchar_t* ap = testString.c_str();
jl_value_t* ptr = jl_new_bits(ptr_dt, (void*)&ap); // pointer to const wchar_t **
```
But If assign e.g. `const wchar_t **` or `std::basic_string,std::allocator > *` program run. If assign `ap` = `const wchar_t *`, `testString.c_str()` or `testString.data()` the program fail. This is not good, because the function `jl_new_bits` expects `void * data`.
Why I need to assign pointer to pointer instead of pointer?
Thanks.
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