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From: avg@hq.demos.su (Vadim G. Antonov)
Newsgroups: comp.unix.questions
Subject: Re: Strcpy on SysV vs. BSD.
Message-ID: <1990Sep1.194237.2459@hq.demos.su>
Date: 1 Sep 90 19:42:37 GMT
References: <24351@adm.BRL.MIL>
Reply-To: avg@hq.demos.su (Vadim G. Antonov)
Organization: DEMOS, Moscow, USSR
Lines: 33

In article <24351@adm.BRL.MIL> hsw@sparta.com (Howard Weiss) writes:

> Here is a short C program that demonstrates the problem:
>
>main(){
>  char *TTx = "/dev/";
>  char tty[10]; /* works on both SysV and BSD */
>/*  char *tty;	/* works only on BSD */
>  strcpy(tty,TTx);
>  printf("what's in tty now is %s\n",tty);
>}
>
>Yet, the 'char *tty' compiles and runs fine on BSD!

	Generally speaking, it SHOULD NOT work because the only
	thing this program do (commented version) is writing
	bytes "/dev/" into some undefined place pointed by
	uninitialized pointer `tty'. You're lucky: Sys V catched
	you and did not allow you to make a hard mistake.
	Errors of such sort are very easy to put and very hard
	to get (out of the program).

>I've worked on UNIX systems since V6 (in 1976) and I've never seen
>this before.

	I've also worked on Unix V6; but I've ran across
	uninitialized pointers many times! :-)

>Howard Weiss

	Vadim Antonov,
	DEMOS, Moscow, USSR
	(it is NOT a joke)