Thanks again.
What is jl_init("/Users/inorton/git/jl71/usr/lib/")?
On Saturday, September 10, 2016 at 12:44:32 AM UTC+8, Isaiah wrote:
>
> (Disregard my suggestion about `Ptr{TestType}`, `jl_call1` only takes
> boxed arguments so that won't work)
>
> The problem is that the passed argument type does not match any available
> method (because it isn't actually passed a julia type at all) so `jl_call1`
> silently gives up. The `jl_call*` methods are in TRY/CATCH blocks to
> prevent spilling errors across the API, and they do not print error
> messages.
>
> The following example works, it's not really efficient but it does
> demonstrate type construction from C:
>
> #include <julia.h>
> #include <iostream>
> using namespace std;
>
> struct TestType {
> double a;
> double b;
> };
> int main(int argc, char *argv[])
> {
> TestType A, *ret;
> A.a=2.;
> A.b=3.;
> jl_init("/Users/inorton/git/jl71/usr/lib/");
> jl_load("TestArg.jl");
> jl_value_t * mod = (jl_value_t*)jl_eval_string("TestArg");
>
> // construct a TestType instance
>
> jl_value_t* jl_A =
> jl_new_struct((jl_datatype_t*)jl_get_function((jl_module_t*)mod,
> "TestType"),
> jl_box_float64(A.a),
> jl_box_float64(A.b));
>
> jl_function_t * func = jl_get_function((jl_module_t*)mod,"TestFunc");
> jl_call1(func, jl_A);
>
> jl_atexit_hook(0);
> return 0;
> }
>
>
> Using the embedding API requires a substantial depth of understanding of ,
> including stack vs heap and argument passing, as well as dynamic language
> concepts such as boxing, and rooting. The embedding section of the manual
> is designed to provide an overview, but ultimately you are going to have to
> read and grok the Julia source to get every little detail.
>
> On Fri, Sep 9, 2016 at 9:23 AM, K leo <cnbi...@gmail.com <javascript:>>
> wrote:
>
>> Isaiah,
>>
>> Thanks for the reply.
>>
>> I tried your advice A, i.e. "change to an immutable on julia side, and
>> change function signature to 'Ptr{TestType}'", and the code behaves the
>> same as before, i.e. it compiles OK and runs OK but does not show the
>> output of the println in the function.
>>
>> I guess at the moment what puzzles me is not whether the data get passed
>> correctly (because I am not trying to access the data yet), but why the one
>> single statement in the Julia function is not executed. That function
>> appears to be taken correctly because if I change the function name in
>> Julia then there is a core dump. Any thoughts?
>>
>> I have not yet tried your advice B as I am not too clear about it.
>>
>>
>> On Friday, September 9, 2016 at 8:52:30 PM UTC+8, Isaiah wrote:
>>>
>>> In c, 'struct TestType' is plain old data, not a Julia type
>>> (jl_value_t). Either change to an immutable on julia side, and change
>>> function signature to 'Ptr{TestType}'; or allocate a 'jl_value_t*' with
>>> the correct type tag, and set the fields.
>>>
>>> On Friday, September 9, 2016, K leo <cnbi...@gmail.com> wrote:
>>>
>>>> I tried the following, it compiles OK and runs OK, but it appears the
>>>> julia function is not called (because there is no output from the println
>>>> statement). What is wrong?
>>>>
>>>> #include <julia.h>
>>>>> #include <iostream>
>>>>> using namespace std;
>>>>> struct TestType {
>>>>> double a;
>>>>> double b;
>>>>> };
>>>>> int main(int argc, char *argv[])
>>>>> {
>>>>> TestType A, *ret;
>>>>> A.a=2.;
>>>>> A.b=3.;
>>>>> jl_init(NULL);
>>>>> jl_load("TestArg.jl");
>>>>> jl_value_t * mod = (jl_value_t*)jl_eval_string("TestArg");
>>>>> jl_function_t * func =
>>>>> jl_get_function((jl_module_t*)mod,"TestFunc");
>>>>> jl_call1(func, (jl_value_t *)&A);
>>>>> jl_atexit_hook(0);
>>>>> return 0;
>>>>> }
>>>>> # TestArg.jl
>>>>> module TestArg
>>>>> type TestType
>>>>> a::Float64
>>>>> b::Float64
>>>>> end
>>>>> function TestFunc(data::TestType)
>>>>> println("in TestArg.TestFunc ")
>>>>> end
>>>>> end
>>>>
>>>>
>>>>
>
