MATLAB: How to add additional linker flags to the generated makefile

additional_ldflagsEmbedded Coderflagslinker

I am generating C/C++ code from a Simulink model using Simulink Coder or Embedded Coder.

When I try to compile the generated code by running the .bat file, I get a linking error complaining about a conflict between LIBCMT and MSVCRT, with a suggestion to add the /NODEFAULTLIB:libname option to the linker flags.

I have found that adding this option to the ADDITIONAL_LDFLAGS field of the generated .mk file solves the issue. How can this option be automatically added to the generated makefile?

Best Answer

You can add link options to the model build information by using the "addlinkflags" function. To learn more, see the following documentation page:

https://www.mathworks.com/help/releases/R2020a/rtw/ref/addlinkflags.html

To add the additional linker flags to the makefile, follow below steps:

1) Create a MATLAB function setBuildArgs.m with the following code inside:

function setBuildArgs(buildInfo)
linkFlags={'/NODEFAULTLIB:libname'};
addLinkFlags(buildInfo,linkFlags);

2) Open the model you want to generate code from, execute the following command:

>> set_param(gcs,'PostCodeGenCommand','setBuildArgs(buildInfo)');

3) Generate code and check the .mk file. The flag /NODEFAULTLIB:libname should now appear in the ADDITIONAL_LDFLAGS field.

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Codegen('mex') does not support custom toolchains, as noted in the documentation at the following link:

https://www.mathworks.com/help/coder/ug/use-the-custom-toolchain.html

Compiler settings are inherited from the "mex -setup" command.

Instead, you can use the Post-Code-generation command to pass a custom Build Information Object to the "codegen" command.

For example, you could add a link flag with the following function:

function setbuildargs(buildInfo)
     linkFlags = {'-lpthread'};
     buildInfo.addLinkFlags(linkFlags);
     cfg = coder.config('mex');
end

That function can then be used to pass the build information object via the PostCodeGenCommand:

>> cfg.PostCodeGenCommand = 'setbuildargs(buildInfo)';

More information and further examples can be found in the documentation at the following link:

https://www.mathworks.com/help/coder/ug/customizing-the-post-code-generation-build-process.html

MATLAB: When using custom code in Simulink, how to look at stack trace information from a custom code crash

Use a MATLAB Function Block in your model containing the following code:

coder.updateBuildInfo('addCompileFlags', '/Zi');
coder.updateBuildInfo('addLinkFlags', '/DEBUG');

Change the compile and link flags to be the appropriate flags for your compiler to produce debugging symbols.

Upon simulation, debugging symbols (if created as a separate file) will be produced in the directory (where <model> is the name of your model):

<currentFolder>\slprj\_sfprj\<model>\_self\sfun\src\

From the stack trace that appears in the Details view of the MATLAB crash window, use a tool that can read debugging symbols to determine the function and line number of each frame in the stack trace.

Best Answer

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