Extract directory from filename

I need to extract the directory ****tion from a filename string (e.g. 
c:\foo\bar.txt).

I came across the following splitpath function through a bit of 
searching around. I figured that the second and third parameters are 
pointers to character arrays which will be filled when the function 
returns. But I can't understand how those pointers have to be passed to 
it. I tried this which fails -

void main()
{
	char **dirpart;
	char **filepart;
	splitpath("c:\\foo\\bar.txt", dirpart, filepart);
}

int splitpath(char *path, char **dirpart, char **filepart)
{
     static char	DOT[] = ".";
     char	*dpart;
     char	*fpart;

     if ((fpart = strrchr(path, '/')) == NULL)
	{
		if ((dpart = strdup(DOT)) == NULL)
			return -1;

		if ((fpart = strdup(path)) == NULL)
		{
			free(dpart);
			return -1;
		}
     }
     else
	{
		if ((dpart = strdup(path)) == NULL)
			return -1;

		dpart[fpart - path] = '0';
		if ((fpart = strdup(++fpart)) == NULL)
		{
			free(dpart);
			return -1;
		}
     }

     *dirpart = dpart;
     *filepart = fpart;

     return 0;
}

Somebody shed some light here?

..p