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: 13 rules found
lock-in
    Impact
      Clean code attribute
        1. "<time.h>" should not be used

           Code Smell
        2. "<stdio.h>" should not be used in production code

           Code Smell
        3. "<signal.h>" should not be used

           Bug
        4. Preprocessor operators "#" and "##" should not be used

           Code Smell
        5. Bitwise operators should not be applied to signed operands

           Bug
        6. Bit fields should be declared with appropriate types

           Code Smell
        7. Multicharacter literals should not be used

           Code Smell
        8. Arguments evaluation order should not be relied on

           Bug
        9. "#include_next" should not be used

           Code Smell
        10. GNU extensions should not be used

           Code Smell
        11. The "sizeof" and "alignof" operator should not be used with operands of a "void" type

           Bug
        12. Keywords introduced in later specifications should not be used as identifiers

           Code Smell
        13. Control should not be transferred into a complex logic block using a "goto" or a "switch" statement

           Code Smell

        GNU extensions should not be used

        consistency - conventional
        maintainability
        Code Smell
        • lock-in
        • obsolete
        • gnu

        Why is this an issue?

        Proprietary compiler extensions can be handy, but they commit you to always using that compiler. This rule raises an issue when GNU extensions are used, such as:

        • Ternary operator with omitted second operand
        • Case ranges in switch statements
        • Expression statements, i.e. code blocks producing value
        • Index range in array initializers
        • A array initializer without =
        • A structure member initializer with a colon
        • Decimal floating points numbers _Decimal32, _Decimal64, and _Decimal128
        • Structures and union without named data members
        • Empty initializers = {} in pre-C23 code, as the feature was standardized in C23

        Noncompliant code example

        struct S {
          int f;
        };
        
        struct S s[] = {
          [0] { // Noncompliant
            f : 0 // Noncompliant
          }
          [1 ... 3] = { // CHECK :8 :11 S3715:use of GNU array range extension
            .f = 2
          }
        };
        
        int fun(int p) {
          switch (p) {
            case 0 ... 1: // Noncompliant
              do_the_thing();
              break;
            case 2:
              //...
          }
        
          p = ({ // Noncompliant
            int a = 10, b = 20;
            (a * b) + 10;
          });
        
          return p ?: 0; // Noncompliant
        }
        
        _Decimal32 d32; // Noncompliant
        
        struct Empty {}; // Noncompliant in C
        

        Compliant solution

        struct S {
          int f;
        };
        
        struct S s[] = {
          [0] = {
            .f = 0
          },
          [1] = {
            .f = 2
          }
          [2] = {
            .f = 2
          },
          [3] = {
            .f = 2
          }
        
        };
        
        int fun(int p) {
          switch (p) {
            case 0:
            case 1:
              do_the_thing();
              break;
            case 2:
              //...
          }
        
          int a = 10, b = 20;
          p = (a * b) + 10;
        
          return p ? p: 0;
        }
        
          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