C - freopen or freopen_s

These functions, declared inside stdio.h, both have one thing that I couldn't find the use of:


== FILE * freopen( "asd.txt", "r+", oneFILE*variable ); ==

Why does this shit return a (FILE *)?
- The oneFILE*variable gets its previously held file closed, all good.
- The oneFILE*variable gets loaded with the "asd.txt" with "r+" attribute, all good.

Then the function fucking returns the same pointer, again, the same thing that has been fucking stored inside the oneFILE*variable, why?


== errno_t freopen_s( ONEdummyFILE**variable, "asd.txt", "r+", oneFILE*variable ) ==

Same shit again, why am I giving a retarded, no-use, dummy FILE** variable?

What the fuck is this? Does it have another explanation?

>...and then your program will die horribly if anything bad happens to the file after you open it the first time.

Explain... I am planning to use something like this:

if ( freopen( "some.txt", "r+", someFILEpointer ) ) {
    /* do things with the file */
}
else {
    printf_s( "Your file could not be opened for writing" );
    /* don't do things with the file */
}

What bad is to happen to my file? I don't get it...