Re: const static data member from abstract class crashes my program

=?ISO-8859-1?Q?Daniel_Kr=FCgler?= <>
Fri, 27 Aug 2010 05:29:42 CST
On 27 Aug., 05:06, sil <> wrote:

Thanks in advance for any help / insight on this matter.

1) This piece of code (inside the class ReassignCaseRequestHandler :
public CaseRequestHandler implementation file) calls a const static
data member (CaseRequestHandler::PARAM_CALLING_TRANSACTION) (see code
below). The problem I am having is that this static data member (first
param to MessageParameter) is uninitialized (bss section).


const MessageParameter*
ReassignCaseRequestHandler::requestParameters1[] =
MessageParameter( CaseRequestHandler::PARAM_CALLING_TRANSACTION, true,
1, 20, MessageParameter::ALPHA_NUMERIC ),

  addRequestVersion( 1, requestParameters1 );

2) Here's how the CaseRequestHandler::PARAM_CALLING_TRANSACTION is
initialized in the base class:

In the header file:
class CaseRequestHandler
  static const string PARAM_CALLING_TRANSACTION;

In the .cpp file:
using namespace std;

#include <string>
#include "CaseRequestHandler.h"

const string CaseRequestHandler::PARAM_CALLING_TRANSACTION =

Without looking into the details it looks to me as if
you are attempting to access a global variable defined
in translation unit (TU) A within TU B where the variable
has not yet been initialized. Note that the initialization
order among variables in different TUs is unspecified. In
fact, the situation is even worse in the sense that the
initialization of such variables is unsequenced.

To fix your problem, you could use a function with
a local static variable, e.g.

// Header:
class CaseRequestHandler
   static const string& param_calling_transaction();


// Cpp:

const string& CaseRequestHandler::param_calling_transaction()
   static const string result("CALLING_TRANSACTION");
   return result;

Local static variables are initialized when the code flow
reaches them the first time and succeeds.

HTH & Greetings from Bremen,

Daniel Kr?gler

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