WORD_BIT vs LONG_BIT

What is the difference between WORD_BIT and LONG_BIT? And which one should I use to find out the word size of my system? Both return different results

➜  ~ getconf LONG_BIT
64
➜  ~ getconf WORD_BIT
32
➜  ~

I also read in some other post that a reliable way to find out word size can be to print the size of void. This gives me 8 bytes.

printf("%d\n", (int)sizeof(void*));

Will this always be equal to the result returned by getconf LONG_BIT? Sorry, sneaking one more question here - word size is related to the CPU architecture. Will OS also work on the same word size that CPU architecture has defined?