[cs631apue] function forward declarations

[Jan Schaumann]

Timothy Wang <twang77 at stevens.edu> wrote:

> This leads me to believe that the underlying
> implementation of getlogin is written in the OS
> itself and C code will only have to declare the
> function either through unistd.h or writing ?char  *
> getlogin(void);?.

Any other takers?

What about other functions, like, say, "printf" or
"open" and "close"?

Can we forward declare those ourselves, or must we
include a header for them?

-Jan