PHP including functions from another file.
 

If I have a form that includes another php file (let's call it B) with functions, but such form includes a different php file (called C) when it submits, will functions from B be accessible from within C?

Yes it can be called.

yes............................................... .................

Include and require are identical, except upon failure:

require will produce a fatal error (E_COMPILE_ERROR) and stop the script
include will only produce a warning (E_WARNING) and the script will continue

yeah you can say

include function
 

Include function is used for include more files for embedded one file.The use of include file attaching more files with working file.......