Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!wuarchive!udel!haven!adm!smoke!gwyn
From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: prototypes, NULL, and magic
Message-ID: <15676@smoke.brl.mil>
Date: 2 Apr 91 22:06:27 GMT
References: <1490@sheol.UUCP> <15588@smoke.brl.mil> <1561@sheol.UUCP>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 14

In article <1561@sheol.UUCP> throopw@sheol.UUCP (Wayne Throop) writes:
>So, specifically: under the upcoming BSD release, with prototypes in
>scope, is it really safe to use unadorned NULL to terminate a
>variable argument list a-la execl(2) family as Chris seemed to
>imply (but did not explicitly state)?  Or did I misunderstand?

No, that would depend on the implementation.  If NULL is defined as
0 (which is always allowed for a standard-conforming implementation),
there could easily be a problem.  The prototype does not specify the
types of the ,... arguments, so no automatic argument conversion
will be done for them.  If NULL is defined as ((void*)0), for
example, then it should work, only because void* and char* are
required to have the same representation (so if a char* is expected,
a void* can be passed for the actual argument).