>>Note that Forsyth's example is from 6th edition Unix, not 7th edition.
>>(The "s4/" in the source file name is a dead giveaway.)

i'm afraid not.

>>C didn't really become widely used until after the 7th edition, and
>>v7 C is really the ancestral root of most other implementations.  It is

the C compilers knew nothing of main, and if 7th edition really was the ancestral
root of most other implementations (which isn't so, because there were
some before 7th edition), they wouldn't have needed the invention
of EXIT_FAILURE and EXIT_SUCCESS.