Re: misleading statement in bugs.html#known

[Andreas Schwab <schwab@suse.de>]

Per Bothner <per@bothner.com> writes:

|> The bugs.html files says 'FILE *yyin = stdin' "will not compile with GNU
|> libc (GNU/Linux libc6), because stdin is not a constant. This was done
|> deliberately, in order for there to be no limit on the number of open FILE
|> objects."
|> 
|> The latter has nothing to do with it.  It is easy to make stdin be
|> a constant while still having no limit on the number of open FILE
|> objects.  For example:
|> 
|> 	extern FILE __stdin;
|>          @define stdin (&__stdin)
|> 
|> The point is that glibc allows you to *assign* to stdin, so it is
|> no longer constant.  This is a questionable feature..

No.  The real reason is that using the address of a static object is a
nightmare in context of maintaining binary compatibility.  Platforms that
use copy relocations will lose if the size of the FILE type changes.

In any way, the C standard does not *require* stdin to be a constant.
Thus using it as an initializer at file scope is broken no matter what.

Andreas.

-- 
Andreas Schwab                                  "And now for something
Andreas.Schwab@suse.de				completely different."
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