coder.extrinsic('function_name');
coder.extrinsic('function_name_1',
... , 'function_name_n');
coder.extrinsic('-sync:on', 'function_name');
coder.extrinsic('-sync:on', 'function_name_1',
... , 'function_name_n');
coder.extrinsic('-sync:off','function_name');
coder.extrinsic('-sync:off', 'function_name_1',
... , 'function_name_n');
function_name
function_name_1,
... , function_name_nDeclares function_name or function_name_1 through function_name_n as
extrinsic functions.
–sync:onfunction_name or function_name_1 through function_name_n.
Enables synchronization of global data between MATLAB® and
MEX functions before and after calls to the extrinsic functions, function_name or function_name_1 through function_name_n.
If only a few extrinsic calls modify global data, turn off synchronization
before and after all extrinsic function
calls by setting the global synchronization mode to At MEX-function
entry and exit. Use the –sync:on option
to turn on synchronization for only the extrinsic calls that do modify
global data.
For constant global data, enables verification
of consistency between MATLAB and MEX functions after calls to
the extrinsic functions, function_name or function_name_1 through function_name_n.
–sync:offDisables synchronization of global data between MATLAB and
MEX functions before and after calls to the extrinsic functions, function_name or function_name_1 through function_name_n.
If most extrinsic calls modify global data, but a few do not, you
can use the –sync:off option to turn off
synchronization for the extrinsic calls that do not modify
global data.
For constant global data, disables verification
of consistency between MATLAB and MEX functions after calls to
the extrinsic functions, function_name or function_name_1 through function_name_n.
coder.extrinsic declares extrinsic functions.
During simulation, the code generator produces code for the call to
an extrinsic function, but does not produce the function's internal
code. Therefore, simulation can run only on platforms where MATLAB software
is installed. During standalone code generation, MATLAB attempts
to determine whether the extrinsic function affects the output of
the function in which it is called — for example by returning mxArrays to
an output variable. Provided that there is no
change to the output, MATLAB proceeds with code generation, but
excludes the extrinsic function from the generated code. Otherwise,
compilation errors occur.
You cannot use coder.ceval on functions
that you declare extrinsic by using coder.extrinsic.
coder.extrinsic is ignored outside of code
generation.
The code generator detects calls to many common visualization
functions, such as plot, disp,
and figure. The software treats these functions
like extrinsic functions, but you do not have to declare them extrinsic
using the coder.extrinsic function.
Use the coder.screener function
to detect which functions you must declare extrinsic. This function
opens the code generations readiness tool that detects code generation
issues in your MATLAB code.
During code generation, MATLAB attempts to determine
whether the extrinsic function affects the output of the function
in which it is called—for example, by returning mxArrays to
an output variable. Provided that there is no
change to the output, MATLAB proceeds with code generation, but
excludes the extrinsic function from the generated code. Otherwise,
a MATLAB issues a compiler error.
The following code declares the MATLAB function patch as extrinsic in the MATLAB local
function create_plot.
function c = pythagoras(a,b,color) %#codegen
% Calculates the hypotenuse of a right triangle
% and displays the triangle as a patch object.
c = sqrt(a^2 + b^2);
create_plot(a, b, color);
function create_plot(a, b, color)
%Declare patch as extrinsic
coder.extrinsic('patch');
x = [0;a;a];
y = [0;0;b];
patch(x, y, color);
axis('equal');By declaring patch as
extrinsic, you instruct the code generator not to compile or produce
code for patch. Instead, the code generator dispatches patch to MATLAB for
execution.