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Check usage of character vector inside MATLAB Function block

Check ID: mathworks.maab.na_0021

Guideline: na_0021: Strings in MATLAB® functions


Identifies character vectors that are used in MATLAB Function blocks.

MATLAB Functions store strings as character arrays. Due to lack of dynamic memory allocation, the arrays cannot be re-sized to accommodate a string value of different length. Strings are not a supported data type in Simulink®, so MATLAB Function blocks cannot pass the string data outside the block.

This check requires a Simulink Check™ license.

Check Parameterization

This check does not include sub-checks because the MAB modeling guideline provides only one sub ID.

For reference, the MAB guideline sub ID(s) that are recommended for use by the NA-MAAB and JMAAB modeling standards organizations are:

  • NA-MAAB — a

  • JMAAB — a

You can use Model Advisor Configuration Editor to configure this check to include files with a .m extension in the analysis. To enable this feature, in the Input Parameters section, select Check external .m files referenced in the model.

Results and Recommended Actions

ConditionRecommended Action
MATLAB Function block contains a character vector.Consider using enumerations instead of character vectors.

Capabilities and Limitations

  • This check does flags direct string substitutions only.

  • Does not flag strings in MATLAB

  • Does not flag character vectors that are hard-coded into the class definition.

  • Runs on library models.

  • Analyzes content in masked subsystems. By default, the input parameter Look under masks is set to graphical.

  • Analyzes content of library-linked blocks. By default, the input parameter Follow links is set to on.