Modeling Style

hisl_0061: Unique identifiers for clarity

ID: Titlehisl_0061: Unique identifiers for clarity
DescriptionWhen developing a model:
AUse unique identifiers for Simulink® signals.
BDefine unique identifiers across multiple scopes within a chart.
NotesThe code generator resolves conflicts between identifiers so that symbols in the generated code are unique. The process is called name mangling.
RationaleA, BImprove readability of a graphical model and mapping between identifiers in the model and generated code.
Model Advisor CheckCheck Stateflow charts for uniquely defined data objects (Simulink Check)
References

  • DO-331, Section MB.6.3.2.b 'Low-level requirements are accurate and consistent'

  • IEC 61508-3, Table A.3 (2) ‘Strongly typed programming language’

  • IEC 61508-3, Table A.3 (3) - Language subset

  • IEC 61508-3, Table A.4 (5) - Design and coding standards

  • IEC 62304, 5.5.3 - Software Unit acceptance criteria

  • ISO 26262-6, Table 1 (1b) - 'Use of language subsets'

  • ISO 26262-6, Table 1 (1e) - 'Use of well-trusted design principles'

  • ISO 26262-6, Table 1 (1f) - 'Use of unambiguous graphical representation'

  • ISO 26262-6, Table 1 (1g) - 'Use of style guides'

  • ISO 26262-6, Table 1 (1h) - 'Use of naming conventions'

  • ISO 26262-6, Table 6 (1d) - 'No multiple use of variable names'

  • EN 50128, Table A.3 (1) - Defensive Programming

  • EN 50128, Table A.4 (8) 'Strongly Typed Programming Language'

  • EN 50128, Table A.4 (11) - 'Language Subset'

  • EN 50128, Table A.12 (1) 'Coding Standard'

  • EN 50128, Table A.12 (2) 'Coding Style Guide'

See AlsoModel Configuration Set Customization (Embedded Coder)
Last ChangedR2024a
Examples

Not Recommended

In the following example, two states Scope_1 and Scope_2 use local identifier IntCounter.

The identifier IntCounter is defined for two states, Scope_1 and Scope_2.

Recommended

To clarify the model, create unique identifiers. In the following example, state Scope_1 uses local identifier IntCounter_Scope_1. State Scope_2 uses local identifier IntCounter_Scope_2.

The identifier IntCounter_Scope_1 is defined for state Scope_1. Identifier IntCounter_Scope_2 is defined for Scope_2.

hisl_0062: Global variables in graphical functions

ID: Titlehisl_0062: Global variables in graphical functions
Description

For data with a global scope used in a function, do not use the data in the calling expression if a value is assigned to the data in that function.

RationaleEnhance readability of a model by removing ambiguity in the values of global variables.
Model Advisor ChecksCheck global variables in graphical functions (Simulink Check)
References

  • IEC 61508–3, Table A.3 (3) 'Language subset'

  • IEC 61508–3, Table A.4 (4) 'Modular approach'

  • IEC 61508–3, A.4 (5) 'Design and coding standards'

  • IEC 62304, 5.5.3 - Software Unit acceptance criteria

  • ISO 26262-6, Table 1 (1b) 'Use of language subsets'

  • ISO 26262-6, Table 1 (1f) 'Use of unambiguous graphical representation'

  • ISO 26262-6, Table 1 (1h) 'Use of naming conventions'

  • ISO 26262-6, Table 6 (1e) - 'Avoid global variables or else justify their usage'

  • EN 50128, Table A.4 (11) 'Language Subset'

  • EN 50128, Table A.12 (1) 'Coding Standard'

  • EN 50128, Table A.12 (2) 'Coding Style Guide'

  • DO-331, Section MB.6.3.2.g 'Algorithms are accurate'

  • MISRA C:2012, Rule 13.2

  • MISRA C:2012, Rule 13.5

  • EXP30-C. Do not depend on the order of evaluation for side effects

Last ChangedR2024a
Examples

Consider a graphical function graphicalFunction that modifies the global data G.

Recommended

Not Recommended