new () causing SEGV

Posted on 2003-03-06
Medium Priority
Last Modified: 2010-04-01
I am trying to run this program. I am getting SEGV when trying to initialize constructs via new(). What is wrong here?

#include <stdlib.h>
#include <iostream.h>
#include <fstream.h>
#include <stdio.h>
#include <string.h>
#include "RWCustomer.h"
#include "RWParts.h"
#include "RWService.h"
#include "RWVehicle.h"
#include "searched.h"
#include "error.h"

class interface {
          fstream transF;
          masterFile *cust;
          masterFile *veh;
          masterFile *srv;
          masterFile *prt;
          searched *where;
          error *report;
          char functionCode[3]; // storage for functionCode's
          char fileCode[3]; // storage for fileCode's
          char keys[20];
          char operation[256];
          interface() {
               fstream transF("xactions1", ios::in|ios::out); // open IO stream
               cust=new customer();
               veh=new vehicle();
               srv=new service();
               prt=new parts();
               where=new searched();
               report=new error();
          int validated();
          int validFunctionCode();
          int validFileCode();
          void deleteRecord(masterFile *mst, int r);
          void changeRecord(masterFile *mst, int r);
          void printIt(masterFile *mst, int r);
          void SPACE() {
               transF.seekg(1,ios::cur); // Move the GET pointer one position
Question by:oscar_wilson
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Expert Comment

ID: 8083233
It could possibly be the that cust,veh,srv,prt are set up as masterFile pointers.  when you use the new operator for these variables they need to be new masterFile()

Expert Comment

ID: 8083477
yes, however, masterFile is an abstract class and creating oderived objects 'defined' as a masterFile is still ok in C++.

Expert Comment

ID: 8083515
I have used gdb to try to see some of the problems.

The stack has two things on it just below,
but right after new parts() is called, the stack goes crazy and tries to access weird memory locations.

(gdb) where
#0  service::service (this=0x2be50) at service.cpp:51
#1  0x000158dc in main () at main.cpp:21
(gdb) s
main () at main.cpp:22
22              prog->prt=new parts();
(gdb) where
#0  main () at main.cpp:22
(gdb) s

Program received signal SIGSEGV, Segmentation fault.
0xff241f74 in ?? ()
(gdb) where
#0  0xff241f74 in ?? ()
#1  0xff241b10 in ?? ()
#2  0xff2418a8 in ?? ()
#3  0xff353f08 in ?? ()
#4  0x00015924 in main () at main.cpp:22
(gdb) Quit
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Expert Comment

ID: 8083537
The stack trace (gdb) that i performed showed a seg fault when calling new parts() but not new cust,veh,srv().

ALso to note, if newparts() is commented out then the seg fault occurs at new searched(), the problem might not be specific..

any help is appreciated.

Accepted Solution

Kocil earned 100 total points
ID: 8084065
How about this ?
   transF("xactions1", ios::in|ios::out); // open here
   // not here      
   fstream transF("xactions1", ios::in|ios::out);


LVL 11

Assisted Solution

cup earned 100 total points
ID: 8084538
Probably need to look at the constructor of masterFile and customer to determine what has gone wrong.

Does masterFile need transF to be passed in?  Doesn't make much sense opening a file and not using it.
LVL 11

Expert Comment

ID: 9889654
No comment has been added lately, so it's time to clean up this TA. I will
leave a recommendation in the Cleanup topic area that this question is:

Answered: Points split between Kocil and cup (a local in the constructor masks the member variable with the same name)

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