Trying to overcome these 6 g++ errors

These are the errors/warnings that g++ is putting out and below each is the relevant code. Any help with clearing these errors up or shedding some light on them would be greatly appreciated. Thank you!

g++ error:

id31.cpp: In function ‘php_var array(int, ...)’:
id31.cpp:462: warning: cannot receive objects of non-POD type ‘class php_var’ through ‘...’; call will abort at runtime
id31.cpp:480: warning: cannot receive objects of non-POD type ‘class php_var’ through ‘...’; call will abort at runtime

relevant code:

#include <stdarg.h>
php_var array(int key = 0, ...)
{
    va_list ap;
    va_start(ap, key);
    php_var arr;
    arr.to_array();
    int i = 0;
    for(int i = 0; i < key / 2; ++i)
    {
        php_var key2 = va_arg(ap, php_var);
        if(key2 == -1)
        {
            bool found = false;
            for(;;)
            {
                for(i = 0;i < arr.keys.size(); ++i)
                {
                    if(arr.keys[i] == (php_var) i)
                        found = true;
                }
                if(found)
                    ++i;
                else
                    break;
            }
            key2 = i;
        }
        php_var val = va_arg(ap, php_var);
        arr.keys.push_back(key2);
        arr.data.push_back(val);
    };
    va_end(ap);
    retu开发者_如何学Pythonrn arr;
}

gcc error:

id31.cpp: In function ‘php_var substr(php_var, php_var, php_var)’:
id31.cpp:511: error: ambiguous overload for ‘operator-’ in ‘str.php_var::container.std::basic_string<_CharT, _Traits, _Alloc>::length [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>]() - pos’
id31.cpp:511: note: candidates are: operator-(size_t, int) <built-in>
id31.cpp:511: note:                 operator-(size_t, double) <built-in>
id31.cpp:511: note:                 operator-(size_t, float) <built-in>
id31.cpp:511: note:                 operator-(size_t, unsigned int) <built-in>
id31.cpp:511: note:                 operator-(size_t, long int) <built-in>

Relevant code:

php_var substr(php_var str, php_var pos, php_var len)
{
    if(len == 0)
        len = str.container.length() - pos;
    return (php_var) str.container.substr(pos, len);
}
php_var substr(php_var str, long pos, long len)
{
    if(len == 0)
        len = str.container.length() - pos;
    return (php_var) str.container.substr(pos, len);
}

gcc error:

id31.cpp:592: error: ambiguous overload for ‘operator-’ in ‘_length - strlen(php_var)()’
id31.cpp:592: note: candidates are: operator-(const char*, const char*) <built-in>
id31.cpp:592: note:                 operator-(const char*, int) <built-in>
id31.cpp:592: note:                 operator-(const char*, int) <built-in>
id31.cpp:592: note:                 operator-(const char*, int) <built-in>
id31.cpp:592: note:                 operator-(int, int) <built-in>
id31.cpp:592: note:                 operator-(int, double) <built-in>
id31.cpp:592: note:                 operator-(int, float) <built-in>
id31.cpp:592: note:                 operator-(int, unsigned int) <built-in>
id31.cpp:592: note:                 operator-(int, long int) <built-in>
id31.cpp:592: note:                 operator-(double, int) <built-in>
id31.cpp:592: note:                 operator-(double, double) <built-in>
id31.cpp:592: note:                 operator-(double, float) <built-in>
id31.cpp:592: note:                 operator-(double, unsigned int) <built-in>
id31.cpp:592: note:                 operator-(double, long int) <built-in>
id31.cpp:592: note:                 operator-(float, int) <built-in>
id31.cpp:592: note:                 operator-(float, double) <built-in>
id31.cpp:592: note:                 operator-(float, float) <built-in>
id31.cpp:592: note:                 operator-(float, unsigned int) <built-in>
id31.cpp:592: note:                 operator-(float, long int) <built-in>
id31.cpp:592: note:                 operator-(unsigned int, int) <built-in>
id31.cpp:592: note:                 operator-(unsigned int, double) <built-in>
id31.cpp:592: note:                 operator-(unsigned int, float) <built-in>
id31.cpp:592: note:                 operator-(unsigned int, unsigned int) <built-in>
id31.cpp:592: note:                 operator-(unsigned int, long int) <built-in>
id31.cpp:592: note:                 operator-(long int, int) <built-in>
id31.cpp:592: note:                 operator-(long int, double) <built-in>
id31.cpp:592: note:                 operator-(long int, float) <built-in>
id31.cpp:592: note:                 operator-(long int, unsigned int) <built-in>
id31.cpp:592: note:                 operator-(long int, long int) <built-in>

relevant code:

php_var _recruit = _length - (php_var)strlen(_flag);
if (_recruit < (php_var)1)
{
    return _flag;

_end_18:
    return (php_var)sprintf((string)(const char*)(php_var)"%0" + (string)(const char*)_length + (string)(const char*)(php_var)"d", _flag);

}

gcc error:

id31.cpp:598: error: cannot convert ‘std::basic_string<char, std::char_traits<char>, std::allocator<char> >’ to ‘char*’ for argument ‘1’ to ‘int sprintf(char*, const char*, ...)’

relevant code:

if (_recruit < (php_var)1)
{
    return _flag;

_end_18:
    return (php_var)sprintf((string)(const char*)(php_var)"%0" + (string)(const char*)_length + (string)(const char*)(php_var)"d", _flag);

}

1. You're passing a php_var object as parameter for variadic function php_var array(int key = 0, ...). This is not allowed. Only POD objects can be passed as variadic parameters.

2. and 3. There's no operator- defined between an int (or the type of _length, don't know what type it is) and a php_var.

3. sprintf takes, as first argument, a char*, while you're passing a std::string to it. Use std::string::c_str() to convert your string to a const char*

POD => Plain old data : varargs have been created for the C language, they can only be used with superstructure that not contain constructor/destructor.

The first error is simple, you just can't pass objects of type php_var as variadic parameters (parameters to functions which specific ... are the parameters).

As for the other errors, hard to say without seeing the definition of php_var itself.

What the heck are you intending when you write: (string)(const char*)(php_var)"%0" ?!

you take a string then cast it to some unknown type, then cast it back to a const char* (which it was to begin with), then force it to be a std::string (which can't be passed to printf)... why?

The last two snippets look like you are trying to let a parameter specify the length attribute of a printf, if you look at the man page for it, you'll see the proper way is to just do this: printf("%*d", width, num);. Simply placing a * where the "width" option is expected tells printf to take it from another passed parameter.

Finally, all of that casting you are doing is a sign of really bad code, when you do things correctly, casting should be a very infrequent occurrence.