Correct or Not or Old-fashioned or Bug

[Richard Caley]

In article <ZHOUMI.91May23102519 at marlboro.nff.ncl.omron.co.jp>, Zhou Mi (zm) writes:

zm> But, there are so many conflicting answers that I feel really 
zm> confusion. Can anyone give me a proper conclusion or answer ??

Me too, so I caved in and asked for divine guidence.

>From K&R, K&R-II and Plaughter and Brodie...

The Old testament, the book of Reference, chapter 11, verse 2:

      ``The apearence of the extern keyword in an external
	definition indicates that storage for the identifiers being
	declared will be allocated in another file. Thus in a
	multi-file program, an external data definition without the
	extern specifier must appear in exactly one of the files.''

The New Testament, the book of Reference, chapter 10, verse 2:

      ``An external object declaration that does not have an
	initialiser, and does not contain the extern specifier, is a
	tentative definition. [...] If no definition for the object
	appears _in_the_translation_unit_, all its tentative
	definitions become a single definition with initialiser 0.''
		[emphasis mine].

The Commentaries:

      ``If a data object declaration is a tentative definition and you
	write no definition for the same object later in the
	translation unit, then the translater allocates storage for
	the data object at the end of the translation unit.''

Someone else will have to do the Tablets of Stone. 

TNT adds a comment that the multi-file version of the rule is
recognised by the standard as a common extension. 

--
rjc at cstr.ed.ac.uk	It was news to me too, too long on Unix.