Why isn't argv[argc]==(char *)0 ?

[Ken Lee]

In article <547.nlhp3 at oracle.nl>, bengsig at oracle.nl (Bjorn Engsig) writes:
=> The execv family of system calls all have  char *argv[]  as their second
=> parameter, and you are required to put an endmarker as  (char *)0  in it.
=> On the other hand, main has  int argc  and  char *argv[]  but here, the
=> endmarker has disappeared. 

Most (all?) UNIXes have argv[argc]==0, though many, especially System V
based ones, don't document it.  Note that p.115 of the new K&R says
"the [ANSI C] standard requires that argv[argc] be a null pointer".

Ken Lee
DEC Western Software Laboratory, Palo Alto, Calif.
Internet: klee at decwrl.dec.com
uucp: uunet!decwrl!klee