Pointer arithmetic

[Kevin D. Quitt]

    I originally posted to comp.lang.c++ (don't know how it got there):

>    What about the subtraction of pointers to get a constant?  I discovered
>that gcc does not allow:
>
>	int = strchr( string, char ) - &string;
>
>to determine the position of char within string.  Is there a (good) reason
>for disallowing this?  BTW, Microsoft C *does* accept this.


    I rapidly received two responses indicating that the & was the problem.
(Nobody picked on using int and char as variables :-)


    The & was "artistic" in my example.  Microsoft C does allow &string,
but provides a warning that the ampersand is ignored.

    The actual code is:


const unsigned char *chars   = "some string"
unsigned char pass[];

    c   = strchr( chars, toupper( pass[ i ]) ) - chars + 1;


    gcc would not accept this no matter what I did.

-- 
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Kevin D. Quitt         demott!kdq   kdq at demott.com
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