Return Array Pointer with ceval

Question

DKalale 2017-11-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/366360-return-array-pointer-with-ceval

回答： Mark McBroom 2017-11-12

I am trying to pass 6 integer values out of a C Function into a variable in Simulink. I am trying this by trying to return a pointer to a fixed size array out of a C Function using the ceval function. I am having trouble with the ceval settings.

My C function is something like...

int * read_variable(void)
{  
/*Static Variable for Counters */
Static int var[6];
/*Read and Assign to Array*/
var[0] = 10U;
var[1] = 11U;
var[2] = 12U;
var[3] = 13U;
var[4] = 14U;
var[5] = 15U;
/* Return point to the array */
return var;                                                                                                                                                                                                                                                                                               
}

What do I need in ceval to get this to work? Below is what I am starting with, but I am hoping someone else has already figured this out.

function var = read
   var = int32(zeros(6,1));
   var = coder.ceval('read_variable',coder.wref(var));
end

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Answer 1

Mark McBroom 2017-11-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/366360-return-array-pointer-with-ceval#answer_290737

As described in the help , coder.ceval() can only return a scalar value. In order to return a vector, you will need to change your C function to have var[6] as an argument rather than a return and then remove the assignment to coder.ceval, since the C function is now a void function. MATLAB code should look like this.

coder.ceval('read_variable',coder.wref(var));