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Re: Detecting Incomplete Array Initialization at Compile Time?

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On 7/21/2016 2:39 PM, David T. Ashley wrote:
> Found a bug related to incomplete array initialization yesterday.  The form of the bug was:
>
> enum
>   {
>   Apples,
>   Oranges,
>   Grapefruits,
>   MaxElements
>   };
>
> int myarray[MaxElements] =
>    {
>    429,
>    258
>    //Oops, missing initializer--not intended.
>    //C-language defaults to 0.
>    };
>
> Question:  Is there any way to detect incomplete initialization at compile-time?  (Any obscure feature of the language I'm not aware of?)
>
> Caveat:  I've oversimplified the problem for the purposes of example.  Also, this occurred in an embedded system, and doing anything at runtime is off the table.
>

This might do what you want:

enum
   {
   Apples,
   Oranges,
   Grapefruits,
   MaxElements
   };

int myarray[] = /* Leave off the array size here. */
    {
    429,
    258
    //Oops, missing initializer--not intended.
    //C-language defaults to 0.
    };

static char MyArraySizeCheck[ ( sizeof(myarray)/sizeof(myarray[0]) )
                               == MaxEmements ? 1 : -1 ];

If the size is "wrong", then the compiler will complain about the "-1" array 
size on "MyArraySizeCheck".

-- 
Kenneth Brody

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Thread

Detecting Incomplete Array Initialization at Compile Time? "David T. Ashley" <dashley@gmail.com> - 2016-07-21 11:39 -0700
  Re: Detecting Incomplete Array Initialization at Compile Time? Ken Brody <kenbrody@spamcop.net> - 2016-07-21 14:47 -0400
    Re: Detecting Incomplete Array Initialization at Compile Time? Keith Thompson <kst-u@mib.org> - 2016-07-21 12:42 -0700
  Re: Detecting Incomplete Array Initialization at Compile Time? Tim Rentsch <txr@alumni.caltech.edu> - 2016-07-21 20:07 -0700

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