SonarSource Rules
  • Products

    In-IDE

    Code Quality and Security in your IDE with SonarQube Ide

    IDE extension that lets you fix coding issues before they exist!

    Discover SonarQube for IDE

    SaaS

    Code Quality and Security in the cloud with SonarQube Cloud

    Setup is effortless and analysis is automatic for most languages

    Discover SonarQube Cloud

    Self-Hosted

    Code Quality and Security Self-Hosted with SonarQube Server

    Fast, accurate analysis; enterprise scalability

    Discover SonarQube Server
  • SecretsSecrets
  • ABAPABAP
  • AnsibleAnsible
  • ApexApex
  • AzureResourceManagerAzureResourceManager
  • CC
  • C#C#
  • C++C++
  • CloudFormationCloudFormation
  • COBOLCOBOL
  • CSSCSS
  • DartDart
  • DockerDocker
  • FlexFlex
  • GitHub ActionsGitHub Actions
  • GoGo
  • HTMLHTML
  • JavaJava
  • JavaScriptJavaScript
  • JSONJSON
  • JCLJCL
  • KotlinKotlin
  • KubernetesKubernetes
  • Objective CObjective C
  • PHPPHP
  • PL/IPL/I
  • PL/SQLPL/SQL
  • PythonPython
  • RPGRPG
  • RubyRuby
  • RustRust
  • ScalaScala
  • SwiftSwift
  • TerraformTerraform
  • TextText
  • TypeScriptTypeScript
  • T-SQLT-SQL
  • VB.NETVB.NET
  • VB6VB6
  • XMLXML
  • YAMLYAML
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: 22 rules found
confusing
    Impact
      Clean code attribute
        1. #include directives in a file should only be preceded by other preprocessor directives or comments

           Code Smell
        2. Loops should not have more than one "break" or "goto" statement

           Code Smell
        3. Switch labels should not be nested inside non-switch blocks

           Code Smell
        4. Appropriate char types should be used for character and integer values

           Code Smell
        5. The first element of an array should not be accessed implicitly

           Code Smell
        6. Multicharacter literals should not be used

           Code Smell
        7. GNU attributes should be used correctly

           Code Smell
        8. Functions which do not return should be declared as "noreturn"

           Code Smell
        9. Functions with "noreturn" attribute should not return

           Bug
        10. "else" statements should be clearly matched with an "if"

           Code Smell
        11. A conditionally executed single line should be denoted by indentation

           Code Smell
        12. Macros should not be redefined

           Code Smell
        13. "#include_next" should not be used

           Code Smell
        14. String literals should not be concatenated implicitly

           Code Smell
        15. Types and variables should be declared in separate statements

           Code Smell
        16. Format strings should be used correctly

           Code Smell
        17. Conditional operators should not be nested

           Code Smell
        18. Increment should not be used to set boolean variables to 'true'

           Code Smell
        19. Loops with at most one iteration should be refactored

           Bug
        20. Deprecated K&R syntax should not be used for function definition

           Code Smell
        21. Redundant pairs of parentheses should be removed

           Code Smell
        22. "/*" and "//" should not be used within comments

           Code Smell

        "else" statements should be clearly matched with an "if"

        intentionality - clear
        maintainability
        Code Smell
        • confusing

        Why is this an issue?

        More Info

        The dangling else problem appears when nested if/else statements are written without curly braces. In this case, else is associated with the nearest if but that is not always obvious and sometimes the indentation can also be misleading.

        This rules reports else statements that are difficult to understand, because they are inside nested if statements without curly braces.

        Adding curly braces can generally make the code clearer (see rule S121 ), and in this situation of dangling else, it really clarifies the intention of the code.

        Noncompliant code example

         if (a)
           if (b)
             d++;
         else     // Noncompliant, is the "else" associated with "if(a)" or "if (b)"? (the answer is "if(b)")
           e++;
        

        Compliant solution

         if (a) {
           if (b) {
             d++;
           }
         } else { // Compliant, there is no doubt the "else" is associated with "if(a)"
           e++;
         }
        
          Available In:
        • SonarQube IdeCatch issues on the fly,
          in your IDE
        • SonarQube CloudDetect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories
        • SonarQube ServerAnalyze code in your
          on-premise CI
          Developer Edition
          Available Since
          9.1

        © 2008-2025 SonarSource SA. All rights reserved.

        Privacy Policy | Cookie Policy | Terms of Use