The ability to call a function pointer fp with the syntax fp() rather than (*fp)() came rather late, I think at Bjarne's suggestion or example. Pretty sure it was not in v7 C, as you observe.

Convenient though the shorthand may be, it always bothered me as inconsistent and misleading. (I am pretty sure I used it sometimes regardless.)

-rob

On Sat, Apr 25, 2020 at 12:48 PM Adam Thornton <athornton@gmail.com> wrote:

On Apr 24, 2020, at 7:37 PM, Charles Anthony <charles.unix.pro@gmail.com> wrote:

On Fri, Apr 24, 2020 at 7:00 PM Adam Thornton <athornton@gmail.com> wrote:
This doesn’t like the function pointer.

$ cc -c choparg.c
choparg.c:11: Call of non-function

Perhaps:

(*fcn)(arg);

We have a winner!

Also, Kartik, dunno where it is on the net, but if you install a v7 system, /usr/src/cmd/c

Adam