CODEWITHSUNDEEP
c++sfmlvariadic-functions
M Tut
M Tut

Reputation: 69

std::bad_alloc error with SFML

I am working on a project with SFML that involves a lot of menus with a lot of buttons, so I am creating functions to take minimal input and automatically create and format these buttons. I had this working splendidly when the function called for already constructed buttons as parameters, but I want to simplify this to take strings, which will be used to construct buttons, which will be stored in a vector. When I tried doing this, I recieved this error:

Unhandled exception at 0x76a7c41f in Menu.exe: Microsoft C++ exception:
std::bad_alloc at memory location 0x003cd0a0..

and I am pointed to this in dbgheap.c:

 for (;;)
    {
        /* do the allocation
         */
here>>> pvBlk = _heap_alloc_dbg_impl(nSize, nBlockUse, szFileName, nLine, errno_tmp);

        if (pvBlk)
        {
            return pvBlk;
        }
        if (nhFlag == 0)
        {
            if (errno_tmp)
            {
                *errno_tmp = ENOMEM;
            }
            return pvBlk;
        }

        /* call installed new handler */
        if (!_callnewh(nSize))
        {
            if (errno_tmp)
            {
                *errno_tmp = ENOMEM;
            }
            return NULL;
        }

        /* new handler was successful -- try to allocate again */
    }

Here is my code, and what I changed.

This function provides no errors:

void page::addLeft(int n, ...)
{
va_list left;
va_start(left, n);
for (int i = 0; i < n; i++)
{
    leftButtons.push_back(va_arg(left, button));
     //takes parameters of type "button", a working custom class
}
va_end(left);
}

This function gives me the unhandled exception: std::bad_alloc

void page::addLeft(int n, ...)
{
va_list left;
va_start(left, n);
for (int i = 0; i < n; i++)
{
    std::string s = va_arg(left, std::string);
     //takes a parameter of type "string" and uses it in the default constructor 
     //of button. the default constructor for button works. 
    leftButtons.push_back(button(s));
}
va_end(left);
}

I am very new to SFML, but I don't think that's the problem here. Any and all help is appreciated.

Upvotes: 1

Views: 746

Answers (1)

ptrehan
ptrehan

Reputation: 84

va_arg doesn't work with std::string. So after first iteration of for loop we are going to reference unknown memory. One way to make your example work is as follows:

void page::addLeft(int n, ...)
{
va_list left;
va_start(left, n);
for (int i = 0; i < n; i++)
{
    std::string s = va_arg(left, const char *);
     //takes a parameter of type "string" and uses it in the default constructor 
     //of button. the default constructor for button works. 
    leftButtons.push_back(button(s));
}
va_end(left);
}

Upvotes: 2

Related Questions