ofstream - strange exit from program

[addle_brains]

Hey, I'm currently looking into steganography and I decided to create a C++ program to hide a txt file in a bmp file as a little learning experience. All this code runs fine, my problem is occurs when saving the fixed BMP data to file. I'm using the MinGW compiler with msys. I put some text to help with debugging:

std::cout << "Processing data";

//Function calls to process data go here (i won't go into it.)

std::cout << "Done!" << std::endl;

std::cout << "-----------------------------------------" << std::endl;

std::cout << "Saving to file...";

OutToFile(); //This function saves the data to a new bmp file.

std::cout << "Done!" << std::endl;

When I run the program, my output is this ($ indicates prompt)

$ ./steg file.txt file.bmp

Processing Data...Done!
----------------------------------------------
Saving to file...

$

The program just ends. No stackdump or anything. Here is the OutToFile function:

void Steg::OutToFile() const{

	ofstream f("final.bmp", ios::binary | ios::trunc); //Filestream for saving

	//test for failure (Exception class exists)
	if(!f) { throw Hiding::Exception(); }
	
	f.write(finalBMP.c_str(), finalBMP.size());

	f.close();
	std::cout << "Done!" << std::endl;

}

The exception is not thrown. (the try and catch are located in my main() function)

I tried removing everything from the function and placing this in it.

std::cout << "Testing" << std::endl;

The program then ran correctly, so I added this.

ofstream f("final.bmp", ios::binary | ios::trunc); //Filestream for saving

And the program failed again. Does anyone have a clue what's happening? I have included the correct headers and using directives because the ifstreams at the start of the program work fine. It's simply when I open this new ofstream that the program just stops in it's tracks and exits.

[robwhit]

if(!f)
{
    cerr << "Fail!/n";
    throw Hiding::Exception();
}