Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!hp4nl!tnoibbc!westc!gjoost
From: gjoost@westc.UUCP (Gertjan van Oosten)
Newsgroups: comp.lang.c
Subject: Re: Compiler Error?
Keywords: "?:" precedence cc assignment
Message-ID: <441@westc.UUCP>
Date: 16 Feb 89 11:30:13 GMT
References: <683@sbsvax.UUCP>
Reply-To: gjoost@westc.UUCP (Gertjan van Oosten)
Organization: West Consulting bv, Delft, The Netherlands
Lines: 41

In article <683@sbsvax.UUCP> greim@sbsvax.UUCP (Michael Greim) writes:
>Consider the following program:
...
>		(j = 2) ? k = 3 : 4;
...
>On 43BSD, SunOS 3.4, ULTRIX 2.0 this compiles with no error.
>
>According to the C books I could get my hands on,
>"?:" has higher precedence than the assignment operators, like
>"=" for instance. (In X3J11 too)

Your quote from the C-books is right, but you should read it more
carefully:
	"?:" has higher precedence than assignment.
	  ^
	  +--- spot the colon there!

So this means, that an expression like:
	a = b ? c : d
is parsed as:
	a = (b ? (c) : d)
"?:" is a ternary operator, with operands b, c and d (assuming that
b and d don't contain unparenthesised expressions containing lower
precedence operators).

>Thus the compiler should find an error in the statement, something
>like "misplaced assignment".

No, it shouldn't.

>SIEMENS SINIX v2.1 finds an error.

Siemens SINIX v2.1 is an error. :-)

               Yours sincerely,

			   G. J. van Oosten.

"Peace on earth and mercy mild, Mother Brown has lost her child.
 Just another forgotten son....."
	Marillion, "Forgotten Sons"