How to resolve this warning MISRA: C ++

Question

Here is the code as below:

  std::stringstream os;

  os << std::hex; // MISRA warning on this line
  os << std::setw(2);
  os << std::setfill('0');

Warning: "Mandatory rule 8-4-4, function identifier used without" & "; or a partisan parameter list"

I can’t solve it, suggest a solution.

Answer 1

Do what the warning says: take the function address:

os << &std::hex;

Answer 2

How easy to use &as suggested?

#include <iomanip>
#include <iostream>
#include <sstream>

int main() {
    std::stringstream os;

    os << &std::hex; // Works with &
    os << std::setw(2);
    os << std::setfill('0');
    os << 13;

    std::cout << os.str() << "\n";
    return 0;
}

Yes, it works too .

---

What is the difference?

• std::hex is a function reference
• &std::hex is a function pointer

, ostream, , . -, MISRA , , , , .

Answer 3

std::hex(std::cout);

std::cout << std::hex;

.

std::cout << &std::hex;

, .

, MISRA "" //. std::hex , - .

Answer 4

os << std::hex;

basic_ostream<charT,traits>& basic_ostream::operator<<(basic_ostream<charT,traits>& (*pf)(basic_ostream<charT,traits>&))

operator<<(), basic_ostream<>. std::hex.

operator<<() . , , :

os << &std::hex;    // makes the function pointer explicit using the & operator

std::hex(os);       // call the `std::hex` function using a normal function call syntax

// or directly call the function that `std::hex(os)` is specified to do:
os.setf(std::ios_base::hex, std::ios_base::basefield);

, MISRA .

Answer 5

, , std:: stringstream . . , "error", std:: bas_alloc, .

http://www.cplusplus.com/reference/ios/ios/exceptions/

Answer 6

, .

:

• std::hex MISRA-.

  a) std::hex.

  b) std::hex. std::hex .

• , std:: hex, , .

  a) .

  b) .

Answer 7

:

• std::hex
• do cout<<&std::hex
• MISRA

, - icky.

, MISRA , - MISRA C ( , )

, .

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