For loop inside a library?

It might be stupid but I am afraid I am missing something here. I wrote a library , cpp, where inside that library there is some code that loop with a for loop. At the beginning I was trying to print from the loop to the serial and I saw nothing. Then, I'v added a delay just for the test, of 100ms , to see if I can see the print, and I dont.

Is the seeped of the "for" loop inside a library is the same as the main loop ?

You obviously can't tell whats wrong without code, but I am trying to understand if libraries are exactly like a code that is inside the main loop ?

Are there things you have to take into consideration writing a library (other then the regular good habits) ? Are loops and whiles are the exact same as the main loop ?

thank you.

A for loop works the same in a .cpp as in a .ino. You know the drill, show us the code if you want help figuring out what you did wrong.

Program instructions, whether from your main code or found in a library, are executed using the same CPU clock.