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Pointer Incrementing Warning

Yaswanth Narvaneni

Hi Friends,
I'm Currently working on C51v6.02 developed by Keil, I'm facing a problem with the compiler when I compile a similar code like this

main()
{
   char xdata *Data_Ptr = 0x0000; /* Pointer to the 0x000 location */

   while(some loop)
   *Data_Ptr++; /* Points to the next data location on the RAM-- here 0x0001 */
}
when I compile this it gives the following warning message, 
 .\FILENAME(LINENUMBER): warning C275: FILENAME: expression with possibly no effect

Is there any way to avoid this warning message?? Thank you,

With Regards,
Yaswanth

Proudly wasting time since 1981

Parents
  • 0 in reply to Yaswanth Narvaneni

    Hmm... Not sure what "the correct way" means. But the rest of the world increments a pointer this way:

    Data_Ptr++;
    Of course, there are other ways:
    ++Data_Ptr;
or
Data_Ptr += 1;
or
Data_Ptr = Data_Ptr + 1;
    Or you can do it this way:
    *Data_Ptr++;
this expression is same as
*(Data_Ptr++);
or
Data_Ptr += 1, *Data_Ptr;
    But the dereferencing operator * is absolutely unnecessary because its result is not used. That's why the compiler gives the warning.
    Regards,
    - Mike

Reply
  • 0 in reply to Yaswanth Narvaneni

    Hmm... Not sure what "the correct way" means. But the rest of the world increments a pointer this way:

    Data_Ptr++;
    Of course, there are other ways:
    ++Data_Ptr;
or
Data_Ptr += 1;
or
Data_Ptr = Data_Ptr + 1;
    Or you can do it this way:
    *Data_Ptr++;
this expression is same as
*(Data_Ptr++);
or
Data_Ptr += 1, *Data_Ptr;
    But the dereferencing operator * is absolutely unnecessary because its result is not used. That's why the compiler gives the warning.
    Regards,
    - Mike

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