buffer overflow

cxel91a · 08-13-2003, 06:57 PM

void createDir()
{
char* dirName = new char[8];
cout<<"Enter the name of the directory : ";
// doesn't work dirName[7] ='\0';
// doesn't work *(dirname + 7)='\0';
//
// I'm trying to get only 8 chars max. When anything over 7
//the program goes in to a continues loop. How can I discard
//all characters after 7 ?

cin.getline(dirName,8);

if(mkdir(dirName,777) < 0)
{
perror("Cannot create directory");
}
mkdir(dirName,777);

delete[] dirName;
}

coolman0stress · 08-13-2003, 08:38 PM

you can use cin.ignore(x); which will ignore the next x value of characters i believe.

devoyage · 08-14-2003, 03:11 PM

Quote:

Originally posted by cxel91a

if(mkdir(dirName,777) < 0)
{
perror("Cannot create directory");
}
mkdir(dirName,777);

delete[] dirName;
}

That second mkdir() might be messing with you. (you already made it by then)

dakensta · 08-14-2003, 05:23 PM

The failbit is being set on cin if you give too many characters to getline.

You need to call cin.clear() before you will be able to do anything with cin again.

To discard everything with ignore( ... ) call it with std::numeric_limits<std::streamsize>::max() as the size.