put a .m file into the simulink ,why can't work?

I pulled a m function model and code as followed

function y = fcn(u1,u2)
coder.extrinsic('loadlibrary','libfunctions','calllib','unloadlibrary');
loadlibrary('DLL_ADD','DLL_ADD.h');
libfunctions DLL_ADD;
G=calllib('DLL_ADD','Add',u1,u2);
unloadlibrary('DLL_ADD');
y = G;

but there are some errors I can't figure out

 Function output 'y' cannot be an mxArray in this context. Consider preinitializing the output variable with a known type.

Function 'MATLAB Function1' (#65.0.232), line 1, column 1:
"function y = fcn(u1,u2)"
Launch diagnostic report.
Errors occurred during parsing of MATLAB function 'MATLAB Function1'(#65)

Answer 1

[Kaustubha Govind]

Since you have declared calllib as an extrinsic function using coder.extrinsic, Simulink is unable to determine the type of 'y' which is required to generate C code from the MATLAB code, for execution. You can preinitialize the size and type of 'y' as the error suggests.

For example, assuming that 'y' is the same size and type as 'u1':

function y = fcn(u1,u2)
coder.extrinsic('loadlibrary','libfunctions','calllib','unloadlibrary');
loadlibrary('DLL_ADD','DLL_ADD.h');
libfunctions DLL_ADD;
G=calllib('DLL_ADD','Add',u1,u2);
unloadlibrary('DLL_ADD');
y = coder.nullcopy(zeros(size(u1)));
y = G;

[euphy]

Thanks for your answer, Now it can works!^_^

[Kaustubha Govind]

euphy: Could you please accept my answer if it resolved the issue? Thanks!

[Peter Fakhry]

excuse me, in my simulink model i am using matrices imported from workspace but now i want to use these matrices from text files so i can generate a .exe file which automatically grabs these text files and use them in simulation. i used matlab function block and wrote a function containing 'textscan' and 'cell2mat' functions but it doesnt work. do you know how to do it? thanks

Answer 2

[pardis ghaziamin]

function e = fcn(teta,p1,p2) %#codegen

p1=[x_r;y_r;teta_r]; p2=[x;y;teta];

e=[cos(teta),sin(teta),0;-sin(teta),cos(teta),0;0,0,1]*[(x_r)-x;(y_r)-y;(teta_r)-teta];

it has Launch diagnostic report. on x_r ,x