In Linux Calc has no function autocomplete. The user could type “=c” and Calc does nothing other than enter his text in the cell. He would expect to see a list of function completions (CONCATENATE, etc.) and he reports (I didn’t check) that Excel gives him a list. Only once he types the “(” character after the function name does LibreOffice show any type of tool-tip showing how to use the function.
Tested on Kubuntu Linux 12.10, confirmed on another machine with Ubuntu Linux 13.04. Both versions were running LibreOffice 4.1.
There is no need for 2 identical feature requests just because the OS is different.
*** This bug has been marked as a duplicate of bug 71779 ***