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C

C static code analysis

Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code

  • All rules 315
  • Vulnerability13
  • Bug76
  • Security Hotspot19
  • Code Smell207

  • Quick Fix 19
Filtered: 16 rules found
unused
    Impact
      Clean code attribute
        1. Non-empty statements should change control flow or have at least one side-effect

           Bug
        2. Unused type declarations should be removed

           Code Smell
        3. Functions that are not used in a project should be removed

           Code Smell
        4. Forward declarations should not be redundant

           Code Smell
        5. Declarations should not be empty

           Code Smell
        6. Conditionally executed code should be reachable

           Bug
        7. Values should not be uselessly incremented

           Bug
        8. Related "if/else if" statements should not have the same condition

           Bug
        9. Unused assignments should be removed

           Code Smell
        10. All code should be reachable

           Bug
        11. Unused local variables should be removed

           Code Smell
        12. Sections of code should not be commented out

           Code Smell
        13. Unused function parameters should be removed

           Code Smell
        14. Unused functions and methods should be removed

           Code Smell
        15. Empty statements should be removed

           Code Smell
        16. Unused labels should be removed

           Code Smell

        Unused local variables should be removed

        intentionality - clear
        maintainability
        Code Smell
        Quick FixIDE quick fixes available with SonarLint
        • unused

        Why is this an issue?

        How can I fix it?

        An unused local variable is a variable that has been declared but is not used anywhere in the block of code where it is defined. It is dead code, contributing to unnecessary complexity and leading to confusion when reading the code. Therefore, it should be removed from your code to maintain clarity and efficiency.

        What is the potential impact?

        Having unused local variables in your code can lead to several issues:

        • Decreased Readability: Unused variables can make your code more difficult to read. They add extra lines and complexity, which can distract from the main logic of the code.
        • Misunderstanding: When other developers read your code, they may wonder why a variable is declared but not used. This can lead to confusion and misinterpretation of the code’s intent.
        • Potential for Bugs: If a variable is declared but not used, it might indicate a bug or incomplete code. For example, if you declared a variable intending to use it in a calculation, but then forgot to do so, your program might not work as expected.
        • Maintenance Issues: Unused variables can make code maintenance more difficult. If a programmer sees an unused variable, they might think it is a mistake and try to 'fix' the code, potentially introducing new bugs.
        • Memory Usage: Although modern compilers are smart enough to ignore unused variables, not all compilers do this. In such cases, unused variables take up memory space, leading to inefficient use of resources.

        In summary, unused local variables can make your code less readable, more confusing, and harder to maintain, and they can potentially lead to bugs or inefficient memory use. Therefore, it is best to remove them.

        Exceptions

        No issue is raised on local variables with the attribute [[maybe_unused]] or unused and object declarations with non-empty arguments.

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