| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 3409.1 | | HNDYMN::MCCARTHY | A Quinn Martin Production | Thu Jan 23 1997 09:04 | 3 |
| 3409.2 | memory corruption | HNDYMN::MCCARTHY | A Quinn Martin Production | Thu Jan 23 1997 10:47 | 4 |
| 3409.3 | SOMETHING NEW??? | TAV02::MILCHIN | | Mon Feb 10 1997 06:15 | 10 |
| HI!
I would like to know if there is any progress in checking of String
class insertion operator (>>) memory leak problem, as described in .0?
I also verified that the problem exists on OPENVMS ALPHA V7.1.
REGARDS!
MICHAEL
P.S.: Is IPMT report for this case preferable?
|
| 3409.4 | not a memory leak, a memory corruptor | HNDYMN::MCCARTHY | A Quinn Martin Production | Mon Feb 10 1997 08:53 | 7 |
| >>class insertion operator (>>) memory leak problem, as described in .0?
It is not a memory leak. The code allocates a buffer of 1024 on the stack
and then calls a lower level routine to put the input into. So, when 1024 is
read in, then the \0 is added - memory corruption.
bjm
|
| 3409.5 | work arounds for code - recommend #2 | HNDYMN::MCCARTHY | A Quinn Martin Production | Mon Feb 10 1997 16:11 | 60 |
| We can think of two possible workarounds.
Solution 1 - using existing String class:
/*
If you know your buffer length is going to
be greater than 1024 chars, use operator>>(const char*)
to read the string into a char buffer and then copy that
buffer into the string, i.e.:
*/
#include <fstream.hxx>
#include <string.hxx>
#include <stdlib.h>
const int MAX_LINE_LENGTH = 4028; // set this to your maximum record length
main()
{
String token1;
ifstream s("test_ifstream.dat");
if (!s) { cerr << "test_ifstream.dat is not found\n"; exit(1); }
while(!s.eof()) {
char buf[MAX_LINE_LENGTH];
s >> buf;
token1 = buf;
cout << token1.length() << endl;
cout << token1 << endl;
}
}
Solution 2 - using new ANSI string class:
/*
Use the new ANSI standard string class. This is available
with DEC C++ V5.5 or later. See Using Guide for hints on
to upgrade from the non-ANSI string class. In your simple
example, all you would have to is change String to string
and compile:
$ CXX/ASSUME=NOHEAD PROG.CXX
$ CXXLINK prog
*/
#include <fstream.h>
#include <string>
main()
{
string token1; // this is the ANSI string class
ifstream s("test_ifstream.dat");
if (!s) { cerr << "test_ifstream.dat is not found\n"; exit(1); }
while(!s.eof()) {
s >> token1;
cerr << token1.length() << '\n';
cerr << token1 << '\n';
}
}
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