Is this how alignment work? (OpenGL)

[yj1214]

Let's say I have an array something like this,

unsigned char firstPixel[] = {255, 255, 255};

(this is single pixel)

and this is my OpenGL alignment code,

glPixelStorei(GL_UNPACK_ALIGNMENT, 4);

This is what I think how OpenGL alignment works,

<address-0><address-1><address-2><address-3>
<myPixel-R><myPixel-G><myPixel-B>< padding >

Am I correct? does alignment works with single pixel(element)? it doesn't matter how long my pixel row is,

for ex. I have a row which is 3 pixels long. It doesn't effect the alignment, does it? thanks.