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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
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  • Bug76
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  • Code Smell207

  • Quick Fix 19
Filtered: 15 rules found
misra-c2004
    Impact
      Clean code attribute
        1. Pointer and reference parameters should be "const" if the corresponding object is not modified

           Code Smell
        2. "abort", "exit", "getenv" and "system" from <stdlib.h> should not be used

           Bug
        3. "offsetof" macro should not be used

           Code Smell
        4. There shall be at most one occurrence of the # or ## operators in a single macro definition

           Code Smell
        5. In the definition of a function-like macro, each instance of a parameter shall be enclosed in parentheses, unless it is used as the operand of # or ##

           Code Smell
        6. #include directives in a file should only be preceded by other preprocessor directives or comments

           Code Smell
        7. Functions should not be defined with a variable number of arguments

           Code Smell
        8. Switch statement conditions should not have essentially boolean type

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

           Code Smell
        10. A cast shall not remove any const or volatile qualification from the type of a pointer or reference

           Code Smell
        11. If a function has internal linkage then all re-declarations shall include the static storage class specifer

           Code Smell
        12. Functions should not be declared at block scope

           Code Smell
        13. Assembly language should be encapsulated and isolated

           Code Smell
        14. "default" clauses should be first or last

           Code Smell
        15. Integral operations should not overflow

           Bug

        Pointer and reference parameters should be "const" if the corresponding object is not modified

        consistency - conventional
        maintainability
        Code Smell
        Quick FixIDE quick fixes available with SonarLint
        • bad-practice
        • misra-c++2008
        • misra-c2004
        • misra-c2012

        Why is this an issue?

        More Info

        Const correctness is an important tool for type safety. It allows for catching coding errors at compile time and it documents the code for maintainers.

        Correctly const-qualifying pointers can be tricky because the indirection they add can also be const.

        For a pointer X * ptr, const can be written in three different places:

        • const X * ptr and X const * ptr are identical and mean that the X object ptr points to cannot be changed.
        • X * const ptr means that the pointer cannot be changed to point to a different X object.

        In a function signature, the first const X * ptr (or its equivalent X const * ptr) is the one that will bring type-safety. It protects against changing the value pointed at.

        void externalFunction(int * a, const int * b);
        
        void myfunc() {
          int a = 1;
          int b = 2;
          externalFunction(&a, &b);
          // a can now have any value
          // We know that b is still '2'
        }
        

        This rule detects when a pointer or reference parameter could be made const

        void myfunc (      int * param1,  // object is modified
                     const int * param2,
                           int * param3, // Noncompliant
                     int * const param4) // Noncompliant: const doesn't qualify what is pointed at.
        {
          *param1 = *param2 + *param3 + *param4;
        }
        
        void increment (int & value,
                        int & increment) // Noncompliant
        {
          value += increment;
        }
        

        When adding all possible const qualifications, we get:

        void myfunc (      int * param1,  // object is modified
                     const int * param2,
                     const int * param3,
                     const int * param4)
        {
          *param1 = *param2 + *param3 + *param4;
        }
        
        void increment (int & value,
                        const int & increment)
        {
          value += increment;
        }
        
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