i want to use variable size vector in Embedded function! use "eml.varsize('var')" but i get this error,Non-scalars of class 'mxArray' are not supported. should use kind of coder.extrinsic in my code?

function [y,a]  = fcn(blksize)
%#codeg

   eml.varsize('y','a');
   coder.extrinsic('dlmwrite');

    coder.extrinsic('fopen');
    coder.extrinsic('fclose');
    coder.extrinsic('fread');

fid=0;
fid=fopen( 'E:\university\arshad\professor\musavi\gps cod\GPS5700kHz.bin');
rawSignal=fread(fid,blksize);
a=1:blksize;
 y=rawSignal;

[Ahmed Fadhil Hassoney]

oh yeah i got the same problem when i run my simulink its show me this message is "embedded matlab does not support variable size growth through the indexing"!

any help please