<![CDATA[MISRA Discussion Forums - 6.8 Declarators (C++)]]> https://forum.misra.org.uk/ Thu, 05 Nov 2026 15:13:48 +0000 MyBB <![CDATA[Rule 8-4-4 Exception for stream manipulators?]]> https://forum.misra.org.uk/showthread.php?tid=1782 Mon, 07 Sep 2026 08:22:54 +0000 cgpzs]]> https://forum.misra.org.uk/showthread.php?tid=1782
Does Rule 8-4-4 imply that we have to write code like this? I do not see any exception for stream manipulators. Our static analyzer is flagging this case.

Code:
std::cout << "Hello World" << &std::endl;
                              ^
]]>
Does Rule 8-4-4 imply that we have to write code like this? I do not see any exception for stream manipulators. Our static analyzer is flagging this case.

Code:
std::cout << "Hello World" << &std::endl;
                              ^
]]> <![CDATA[Rule 8-5-2: what about strings?]]> https://forum.misra.org.uk/showthread.php?tid=1394 Wed, 10 Jan 2018 13:15:14 +0000 jocob]]> https://forum.misra.org.uk/showthread.php?tid=1394 {
char str1[20];
char str2[20];
};

struct Test t =
{
"Hello",
"World"
};

LDRA flags this with 397 S (Array initialisation has insufficient items.) violation of 8-5-2 (Braces shall be used to indicate and match the structure in the non-zero initialization of arrays and structures.)

Looking at the details of the rule in the guidelines, I see why: "The non-zero initialization of arrays or structures requires an explicit initializer for each element."

It seems there should be an exception for initializing a character array with the string syntax, since:
a. the unused characters are implicitly null character 0
b. there is no MISRA compliant way to explicitly add null characters to a "string"

I think MISRA C 2004 has a similar problem, but I haven't looked at 2012 yet.]]> {
char str1[20];
char str2[20];
};

struct Test t =
{
"Hello",
"World"
};

LDRA flags this with 397 S (Array initialisation has insufficient items.) violation of 8-5-2 (Braces shall be used to indicate and match the structure in the non-zero initialization of arrays and structures.)

Looking at the details of the rule in the guidelines, I see why: "The non-zero initialization of arrays or structures requires an explicit initializer for each element."

It seems there should be an exception for initializing a character array with the string syntax, since:
a. the unused characters are implicitly null character 0
b. there is no MISRA compliant way to explicitly add null characters to a "string"

I think MISRA C 2004 has a similar problem, but I haven't looked at 2012 yet.]]> <![CDATA[Rule 8-5-1 Must a non-static class member variable also explicitly initialized in constructor?]]> https://forum.misra.org.uk/showthread.php?tid=1322 Tue, 07 Mar 2017 08:22:02 +0000 ProgCPlusPlus]]> https://forum.misra.org.uk/showthread.php?tid=1322
MISRA C++:2008 Wrote:Each class constructor shall initialize all non-static members of its class.
The example shows a compliant and a non compliant constructor of a class having only member variables of basic numerical type int32_t. It is clear that a member variable of a basic type must be initialized before first read access to avoid an undefined behavior.

But what about non-static members of a class being of type class.

Must a constructor of the class member variable explicitly called in the constructor to be compliant to this rule?

Example:

Code:
class A
{
   public:
      A ( ) : m_a( false )
      {
      }
      bool GetmA ( void )
      {
         return ( m_a );
      }
   private:
      bool m_a;
};


class B
{
   public:
      B ( ) : m_a( false )  // Compliant or non-compliant because of
      {                     // not explicitly calling constructor of m_b?
      }
      B ( const bool a ) : m_a( a ), m_b()  // Definitely compliant
      {
      }
      bool GetmA ( void )
      {
         return ( m_a );
      }
      bool GetmB (void )
      {
          return m_b.GetmA();
      }
   private:
      bool m_a;
      A    m_b;
};

int main ( void )
{
   B b;
   if ( b.GetmB() )
   {
   }
}
The default constructor of class A for member variable m_b is in both constructors of class B called, but in default constructor of class B only implicit according to C++ standard.

Is the default constructor of class B not explicitly calling default constructor of class A for member variable m_b compliant to rule 8-5-1?]]>
MISRA C++:2008 Wrote:Each class constructor shall initialize all non-static members of its class.
The example shows a compliant and a non compliant constructor of a class having only member variables of basic numerical type int32_t. It is clear that a member variable of a basic type must be initialized before first read access to avoid an undefined behavior.

But what about non-static members of a class being of type class.

Must a constructor of the class member variable explicitly called in the constructor to be compliant to this rule?

Example:

Code:
class A
{
   public:
      A ( ) : m_a( false )
      {
      }
      bool GetmA ( void )
      {
         return ( m_a );
      }
   private:
      bool m_a;
};


class B
{
   public:
      B ( ) : m_a( false )  // Compliant or non-compliant because of
      {                     // not explicitly calling constructor of m_b?
      }
      B ( const bool a ) : m_a( a ), m_b()  // Definitely compliant
      {
      }
      bool GetmA ( void )
      {
         return ( m_a );
      }
      bool GetmB (void )
      {
          return m_b.GetmA();
      }
   private:
      bool m_a;
      A    m_b;
};

int main ( void )
{
   B b;
   if ( b.GetmB() )
   {
   }
}
The default constructor of class A for member variable m_b is in both constructors of class B called, but in default constructor of class B only implicit according to C++ standard.

Is the default constructor of class B not explicitly calling default constructor of class A for member variable m_b compliant to rule 8-5-1?]]> <![CDATA[Rule 8-5-2 what is "non-zero initialization"?]]> https://forum.misra.org.uk/showthread.php?tid=1308 Tue, 24 Jan 2017 14:21:53 +0000 grunwald]]> https://forum.misra.org.uk/showthread.php?tid=1308
  • default initialization ("T var;")
    Calls the default constructor (if it exists); otherwise the memory is left uninitialized.

  • value initialization ("T var = {};")
    Calls the default constructor if it exists and is user-defined.
    Otherwise, performs zero-initialization and then calls the compiler-generated default constructor (if it exists).

  • zero initialization
    Roughly equivalent to a memset(..., 0, ...)

    • The term "non-zero initialization" is not defined anywhere.

    Code:
    struct POD { int member1; int member2; };
    class UserDefinedCtor { public: UserDefinedCtor(); };
    struct CompilerDefinedCtor { int member1; UserDefinedCtor member2; };

    POD pod[3] = {}; // value initialization that uses zero initialization
    UserDefinedCtor udc[3] = {}; // value initialization but does not involve zero initialization
    CompilerDefinedCtor cdc[3] = {}; // value initialization that involves both zero initialization and constructor calls

    The declaration `pod` is clearly compliant with Rule 8-5-2.

    What about `udc`? If it is classified as "non-zero initialization", Rule 8-5-2 would require an explicit initializator for each element:
    Code:
    UserDefinedCtor udc[3] = { UserDefinedCtor(), UserDefinedCtor(), UserDefinedCtor() };

    But maybe "zero initialization" in this rule does not refer to the C++ concept, but instead to the syntactic forms "{}", "{0}" and "{NULL}" ?]]>
  • default initialization ("T var;")
    Calls the default constructor (if it exists); otherwise the memory is left uninitialized.

  • value initialization ("T var = {};")
    Calls the default constructor if it exists and is user-defined.
    Otherwise, performs zero-initialization and then calls the compiler-generated default constructor (if it exists).

  • zero initialization
    Roughly equivalent to a memset(..., 0, ...)

    • The term "non-zero initialization" is not defined anywhere.

    Code:
    struct POD { int member1; int member2; };
    class UserDefinedCtor { public: UserDefinedCtor(); };
    struct CompilerDefinedCtor { int member1; UserDefinedCtor member2; };

    POD pod[3] = {}; // value initialization that uses zero initialization
    UserDefinedCtor udc[3] = {}; // value initialization but does not involve zero initialization
    CompilerDefinedCtor cdc[3] = {}; // value initialization that involves both zero initialization and constructor calls

    The declaration `pod` is clearly compliant with Rule 8-5-2.

    What about `udc`? If it is classified as "non-zero initialization", Rule 8-5-2 would require an explicit initializator for each element:
    Code:
    UserDefinedCtor udc[3] = { UserDefinedCtor(), UserDefinedCtor(), UserDefinedCtor() };

    But maybe "zero initialization" in this rule does not refer to the C++ concept, but instead to the syntactic forms "{}", "{0}" and "{NULL}" ?]]>         <![CDATA[Rule 8-4-4 (Required) function identifier with & or ()]]> https://forum.misra.org.uk/showthread.php?tid=1099 Wed, 13 Aug 2014 19:38:15 +0000 Achim Olaf Zacher]]> https://forum.misra.org.uk/showthread.php?tid=1099
    Code:
    std::cout
    ]]>
    Code:
    std::cout
    ]]>         <![CDATA[6.8.5 Initializers and POD]]> https://forum.misra.org.uk/showthread.php?tid=978 Wed, 04 Sep 2013 07:36:51 +0000 martin.dowie]]> https://forum.misra.org.uk/showthread.php?tid=978
    My reading of this rule leads me to the conclusion that "POD" classes are effectively not allowed, since any user-defined constructor provided to give initial values to non-static member data results in the class no longer being POD. Example:

    [code]// Standard headers
    #include
    #include // std::is_pod

    // User-defined structs...how many are POD?
    struct Trivial_Ctor { int i; };
    struct With_User_Defined_Ctor { int i; With_User_Defined_Ctor() { } };
    struct With_Initialised_Member { int i; With_Initialised_Member() : i(0) { } };

    int main()
    {
    std::cout ]]>
    My reading of this rule leads me to the conclusion that "POD" classes are effectively not allowed, since any user-defined constructor provided to give initial values to non-static member data results in the class no longer being POD. Example:

    [code]// Standard headers
    #include
    #include // std::is_pod

    // User-defined structs...how many are POD?
    struct Trivial_Ctor { int i; };
    struct With_User_Defined_Ctor { int i; With_User_Defined_Ctor() { } };
    struct With_Initialised_Member { int i; With_Initialised_Member() : i(0) { } };

    int main()
    {
    std::cout ]]>