Re: Constructor question (again)
JoeC wrote:
gdata is a vector. When I comment out the line the program works but I
get a block instead of my graphic. There seems to be a problem
transfering the graphic data in the vector.
Please learn to quote correctly on Usenet. See
http://en.wikipedia.org/wiki/Top-posting#Inline_replies.
I reproduce and simplify your code here. You seem to think the problem
comes from the marked line:
graphic
{
public:
graphic(const graphic& gr)
{
gdata = gr.gdata; // <---- This line crashes
}
std::vector<BYTE> gdata;
};
If BYTE is a typedef for an unsigned char (or some builtin type), this
line has no reason to crash. It may throw an exception (for memory
allocation problems), but it cannot just "crash" (assuming the library
itself has no bug).
If BYTE is not a builtin type, then it may be its operator= or
something in that class that cause problems.
Having said that, I doubt that the statement itself causes a problem. I
suspect memory gets corrupted before that line. Again:
1) it makes sense semantically to copy that object
2) you are using your library correctly (GDI)
3) the rule of three is respected ("A class with any of {destructor,
assignment operator, copy constructor} generally needs all 3")
4) everything is fine *before* the line where it crashes (undefined
behavior)
Jonathan