Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!itivax!vax3.iti.org!scs
From: scs@vax3.iti.org (Steve Simmons)
Newsgroups: comp.lang.c
Subject: Value, value, who's got the value?
Summary: Why no syntax error?
Message-ID: <1044@itivax.iti.org>
Date: 27 Apr 89 04:48:55 GMT
Sender: news@itivax.iti.org
Reply-To: scs@vax3.iti.org (Steve Simmons)
Organization: Industrial Technology Institute
Lines: 45


Consider the following program:

int	func1()
{
	int b ;

	b = 2 ;
}

int	func2()
{
	int c = 3 ;

	c ;
}

main()
{
	int a = 1 ;
	printf( "Value of a is %d\n", a ) ;
	a = func1() ;
	printf( "Value of a is %d\n", a ) ;
	a = func2() ;
	printf( "Value of a is %d\n", a ) ;
}

Compile and run this on a UNIX-PC (system V) under standard cc or
with gcc, and the result is:
	Value of a is 1
	Value of a is 2
	Value of a is 3

On BSD43. with standard cc or gcc, the result is
	Value of a is 1
	Value of a is 0
	Value of a is 0

Several questions: why does the OS make a difference; why does
System V get it 'right' (even tho the code is wrong); why do
none of these flag func2 as having a syntax error?

   Steve Simmons         Just another midwestern boy
   scs@vax3.iti.org  -- or -- ...!sharkey!itivax!scs
         "Hey...you *can* get here from here!"