functionConst false positive

[Nikita Leontiev]

cppcheck 2.16.0 suggests to use const for method init that changes class member:

enum Type
{
    TYPE_1,
    TYPE_2
};

void getter(int * param)
{
    *param = 1;
}

class Test
{
private:
    Type type;
public:
    Test(): type(TYPE_1) {}

    void init()
    {
        getter(reinterpret_cast<int*>(&type));
    }
};

test\main.cpp:19:7: style: inconclusive: Technically the member function 'Test::init' can be const. [functionConst]
 void init()
      ^

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/13642

[Nikita Leontiev]

cppcheck 2.17.1 generates functionConst false positive with slightly modified code:

#include <cstring>

enum Type
{
    TYPE_1,
    TYPE_2
};

void getter(char * type, int * param)
{
    if (!strcmp(type, "TYPE_2"))
        *param = 1;
}

class Test
{
private:
    Type type;
public:
    Test(): type(TYPE_1) {}

    void init()
    {
        getter("TYPE_2", reinterpret_cast<int*>(&type));
    }
};

test\main.cpp:22:10: style: inconclusive: Technically the member function 'Test::init' can be const. [functionConst]
    void init()
         ^

[CHR]

The FP disappears when getter() takes a const char*. For the original code, there is a warning:

<source>:23:16: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
   23 |         getter("TYPE_2", reinterpret_cast<int*>(&type));
      |                ^~~~~~~~