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Troubleshoot Compiler Issues

Compiler Version Mismatch Errors


The build process produces a compiler version mismatch error.


  1. Check the list of supported and compatible compilers available at

  2. Upgrade or change your compiler. For more information, see Choose and Configure Compiler.

  3. Rebuild the model.

Results for Model Simulation and Program Execution Differ


The program generated for the model produces different results from model simulation results. The generated source code includes an arithmetic operation that produces a signed integer overflow. It is possible that your compiler does not implement wrapping behavior for signed integer overflow conditions. Or, if you are using a compiler that supports wrapping, it is possible that you did not configure it to use the -fwrapv option.

For more information, see C Compiler Considerations for Signed Integer Overflows.


  • If your compiler can force wrapping behavior, turn it on. For example, for the gcc compiler or a compiler based on gcc, such as MinGW, specify the compiler option -fwrapv.

  • Choose a compiler that checks for integer overflows.

  • If you have Embedded Coder®, develop and apply a code replacement library to replace code generated for signed integers.

Generates Expected Code and Produces Unexpected Results


The build process generates expected source code, but the executable program produces unexpected results. The generated source code appears as expected. However, the executable program produces unexpected results.


Do one of the following:

  • Lower the compiler optimization level.

    1. Set the Compiler optimization level configuration parameter to Custom.

    2. In the Custom compiler optimization flags field, specify a lower optimization level.

    3. Rebuild the model.

  • Disable compiler optimizations.

    1. Set Compiler optimization level to Optimizations off (faster builds).

    2. Rebuild the model.

For more information, see Control Compiler Optimizations and your compiler documentation.

Compile-Time Issues


Error is present in the compiler configuration.

Make sure that MATLAB® supports the compiler and version that you want to use. For a list of currently supported and compatible compilers, see If necessary, upgrade or change your compiler (see Choose and Configure Compiler or Choose and Configure Compiler).

Environment variables are incorrectly set up for your make utility, compiler, or linker. For example, installation of Cygwin tools on a Windows platform affects environment variables used by other compilers.

Review the environment variable settings for your system by using the set command on a Windows platform or setenv on a Linux® platform. Make sure that the settings match what is required for the tools you are using.

Error is present in custom code specified as an S-Function block or in Custom Code. For example, the code refers to a header file that the compiler cannot find.

To isolate the source of the problem, remove the custom code from the model, debug, and rebuild the model.

The model includes a block, such as a device driver block, which is not intended for use with the currently selected system target file.

Remove the system target file-specific block or configure the model for use with another system target file.

A linker error about an undefined reference to the data appears when the model build generates an executable program from the model reference hierarchy and these conditions are true:

  • You represent signal, state, or parameter data by creating a data object such as Simulink.Signal. You use the object in a model reference hierarchy.

  • You use a custom storage class with the data object. Custom storage classes require Embedded Coder.

  • You set the owner of the object to a model that does not directly access the data.

To resolve the issue, in the data object, clear the Owner property. Alternatively, set the owner to a model that directly accesses the data.

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