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???
01/10/11 08:28
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#180491 - legality of indexing NULL pointer
Responding to: ???'s previous message
I am not sure about the "legal" status of indexing a NULL pointer (which is what you get when you cast 0 to a pointer). This is the result of the "relaxed" nature of C - as there is no dedicated "nil" pointer, pointer with value 0 has a special status.

You should consider using either a different "starting" pointer, or maybe better use the native absolute addressing through keyword __at (see chapter 3.6 of the Manual).

That SDCC should not throw a FATAL Internal error on this is another issue; but I see that you've already submitted a bug report to the SDCC tracker.

JW


List of 25 messages in thread
TopicAuthorDate
sdcc internal error / C syntax            01/01/70 00:00      
   legality of indexing NULL pointer            01/01/70 00:00      
      bug            01/01/70 00:00      
         version            01/01/70 00:00      
            version revisited            01/01/70 00:00      
               thank you            01/01/70 00:00      
                  Fixed            01/01/70 00:00      
                     no snapshot            01/01/70 00:00      
                        works            01/01/70 00:00      
                           0 is special - but so is NULL. indexing around NULL is bad            01/01/70 00:00      
                              No guarantee that a NULL pointer points to any memory            01/01/70 00:00      
            time            01/01/70 00:00      
               I know :-(            01/01/70 00:00      
       Use of __at ?            01/01/70 00:00      
         What is "that way"?            01/01/70 00:00      
            the antique version....            01/01/70 00:00      
            XBYTE macro            01/01/70 00:00      
               Okay, then the following definition...            01/01/70 00:00      
                  RE: David's remarks about volatility            01/01/70 00:00      
   Close, but no cigar            01/01/70 00:00      
   Avoid the 'volatile'            01/01/70 00:00      
      instead of offsetting...            01/01/70 00:00      
         Dereferencing a '_REG            01/01/70 00:00      
            I agree            01/01/70 00:00      
      Use of __at ? [ed]            01/01/70 00:00      

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