From:	OLIVERWU AT ms4 DOT url DOT com DOT tw (OliverWu)
Newsgroups:	comp.os.msdos.djgpp
Subject:	General Protection Fault when using dynamic_cast<>()
Date:	Mon, 28 Dec 1998 01:19:28 GMT
Organization:	National Taiwan University
Lines:	80
Message-ID:	<3686d822.17161721@news.ntu.edu.tw>
NNTP-Posting-Host:	tawar.m3.ntu.edu.tw
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Hi,
	I'm having trouble running this program. A runtime error,
General Protection Fault, occurs when I'm trying to run the ctor
postfix_statement::postfix_statement(const infix_statement &)

/*--------------------------Program begins--------------------------*/

class element;
class statement_operator: public element;
class statement_operand: public element
class statement;
class infix_statement;
class postfix_statement
{		/* ... */
	public:
		postfix_statement::postfix_statement(const
infix_statement &);
		/* ... */
};

postfix_statement::postfix_statement(const infix_statement &data)
{       content_list_i i;
        list<element> temp; // temp content
        stack<element> temp_operator; // temp operator
        statement_operator test;

        for (i=data.content.begin(); i!=data.content.end(); i++)
                switch (i->e_type())
                {       case 0: // operand
                                temp.push_back(*i);
                                break;
                        case 1: // operator
                                if (i->e_name()==string(")"))

/*problem
                            {
for(;temp_operator.top().e_name()!=string("("); )
                                        {
temp.push_back(temp_operator.top() );
temp_operator.pop();
                                        }
temp_operator.pop(); // pop")"
                                } // consider ")" especially
*/;

                                else

/*problem
                              {       test=*( dynamic_cast<const
statement_operator*>( &(*i) ) );
for(;!prior_to(test,*(dynamic_cast<statement_operator*>(&(temp_operator.top()))));)
                                        {
temp.push_back(temp_operator.top());
temp_operator.pop();
                                        }
temp_operator.push( *(dynamic_cast<conststatement_operator*>(&(*i))));
                                }
*/;

                                break;
                }
}

/*---------------------------Program ends---------------------------*/

	I believe the problem is in those two segments marked by /**/,
but I can't figure it out. Is it possible that I've missed something
in calling dynamic_cast<>()?

	BTW, I compiled this with djgpp 2.8.1, and "gcc -c -Wall",
"gxx -o".


	I'd apperciate anyone's help. Thanx.


OliverWu
b6705019 AT im DOT ntu DOT edu DOT tw
OliverWu
OLIVERWU AT ms4 DOT url DOT com DOT tw

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