Array Allocation Troubles

[CrazyNorman]

I do the following:

    unsigned char* tmp_data = new unsigned char[this->_level_size*this->_level_size*4 + 1];
    tmp_data[this->_level_size*this->_level_size*4] = '\0';

    std::ifstream in_file(levelmap.c_str(), std::ios::in | std::ios::binary);
    in_file.read((char *)&tmp_data,this->_level_size*this->_level_size*4);
    in_file.close();

Yet, it often segfaults. When I run with GDB, it says that the address pointed to by "tmp_data" is "out of bounds." When I run with valgrind, I get similar errors. This code seems like it should be perfectly innocent. What am I doing wrong?

[Salem]

> This code seems like it should be perfectly innocent. What am I doing wrong?
You need to look at how you got to this point.

Like you said, this->_level_size is trash so start by looking at how you create the object in question.

[CrazyNorman]

Sorry, I meant to say that "tmp_data" is out of bounds (or rather the location that it is pointing to). level_size is 1024, and has no trouble whatsoever.

[Salem]

> (char *)&tmp_data
Probably because you're trashing the pointer itself (which is only say 4 bytes), with the 4MB of data you're reading from the file.

Drop the & if you want the data to go into allocated memory.

[CrazyNorman]

Oops. Thanks for pointing that out.