What exactly do these arguments mean in linux?

I have a program written in C and the command I am supposed to run it with on linux looks like this:

./program --something X Y

What exactly does that mean? I think X Y will be the arguments so argc[2] will be X and argc[3] will be Y?

But what about --something?

Thanks a lot!

Answer

The C runtime does not discriminate any arguments, whether they start with -- or not. So you have,

argv[0] = "./program"
argv[1] = "--something"
argv[2] = "X"
argv[3] = "Y"
argv[4] = NULL

It is your program that assigns meaning to those values.