Re: [PATCH] Fix a bug with XEmacs and bignum support.

[Aidan Kehoe <kehoea@parhasard.net>]

 Ar an t-aonú lá déag de mí Eanair, scríobh Reiner Steib: 

 > On Sun, Jan 11 2009, Aidan Kehoe wrote:
 > 
 > > 2009-01-11  Aidan Kehoe  <kehoea@parhasard.net>
 > >
 > > 	* lisp/nnfolder.el (nnfolder-read-folder): 
 > > 	The (lsh -1 -1) trick to generate the greatest positive fixnum
 > > 	value doesn't work under an XEmacs with bignum support; use the
 > > 	most-positive-fixnum constant instead, available since GNU Emacs
 > > 	21.1 and XEmacs 21.1. 
 > 
 > most-positive-fixnum is only available in Emacs 21 when requiring CL.

Oops, you’re right, it was included it in C just after the release. Thanks
for checking.

 > But as CL is required (for ignore-errors), I think this change is
 > fine, so I have installed it.

It’s not, though, it needs to be something like the following in that case,
since CL is available at compile time and not necessarily at runtime: 

--- /tmp/aidan/nnfolder.el.orig	2009-01-11 15:50:39.000000000 +0000
+++ /tmp/aidan/nnfolder.el	2009-01-11 15:50:16.000000000 +0000
@@ -899,7 +899,9 @@
 	      (active (or (cadr (assoc group nnfolder-group-alist))
 			  (cons 1 0)))
 	      (scantime (assoc group nnfolder-scantime-alist))
-	      (minid (lsh -1 -1))
+	      (minid (or (and (boundp 'most-positive-fixnum)
+			      most-positive-fixnum)
+			 134217727))
 	      maxid start end newscantime
 	      novbuf articles newnum
 	      buffer-read-only)

An (eval-when-compile most-positive-fixnum) isn’t appropriate, because the
compile-time constant could be from a 64-bit machine, which would silently
overflow in the Lisp reader under GNU on a 32-bit machine, and break the
algorithm.

-- 
¿Dónde estará ahora mi sobrino Yoghurtu Nghe, que tuvo que huir
precipitadamente de la aldea por culpa de la escasez de rinocerontes?

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