Char * character and string

[Chris Pons]

Hello,
I am trying to work with SDL and one of their functions takes a 
char * file as a function a parameter. However, i'm running into 
trouble how to actually set this variable in my constructor.

I am getting a problem where if I use a pointer to a char and set 
it as "test.bmp" I get an error stating "cannot implicitly 
convert expression (file) of type string to char*. After that I 
decided to try to set file to 'test.bmp' instead, and in that 
case I get: "Unterminated character constant" . Although I am 
familiar with what this error is referring to, I do not know how 
to add a terminator in D.

This is the function that I intend to use the filename in:
**Note the function LoadBMP is the one that REQUIRES a pointer to 
a char
--------------------------------------
	SDL_Surface * Load(char * file)
	{
		SDL_Surface * Temp = null;

		if((Temp = SDL_LoadBMP(file)) == null)
			return null;

		Surface = SDLDisplayFormat(Temp);

		SDL_FreeSurface(Temp);

		return Surface;
	}
----------------------------------------

This is the constructor that is giving me the error:
----------------------------------------------------------
	char * file;
	
	this()
	{
		this.filename = "test.bmp";
	}
-------------------------------------------------------------