MISRA C++:2008 Rule 3-2-1

file1.cpp

                  
                  
typedef          char         char_t;
typedef signed   short        int16_t;
typedef signed   long         int64_t;

namespace bar {
	int64_t a;
	int16_t c;  // Noncompliant

};

file2.cpp

                  
                  
typedef          char         char_t;
typedef signed   int          int32_t;

namespace bar {
	extern char_t c;
	extern int32_t a;
	void foo(void){
		++a;
		++c;
	}
}; 

In this example, the variable bar::c is defined as a char in file2.cpp and as a signed short in file1.cpp. In the target processor i386, the size of these types are not equal. Polyspace flags the definition of bar::c.

The variable bar::a is defined as a long in file1.cpp and as an int in file2.cpp. In the target processor i386, both int and long has a size of 32 bits. Because the definitions of bar::a is compatible in both files, Polyspace does not raise a flag.