Those are Unix manpage section numbers. fseek(3) means fseek in section 3 of the manpages. This can help to differentiate between a command line program and C f

Those are Unix manpage section numbers. fseek(3) means fseek in section 3 of the manpages. This can help to differentiate between a command line program and C function of the same name, for example. See http://www.december.com/unix/ref/mansec.html http://www.december.com/unix/ref/mansec.html