When you assign one class to the other, all you're copying is the pointer, not the memory itself. So they both end up holding pointers to the same memory.
When they go out of scope, they both try to free the same pointer. The first will succeed. The second to go out of scope will crash.
You should create a copy constructor for the class, which will be used whenever you assign another class to it with =.
I am experiencing a difficulty undersatnding why my program (C++, HP UNIX) crashes. It crashes only when I build it with -O (+O2) optimization switch (used in aCC compiler). It works ok with +O0 or +O1 optimization.
Also, I see that local variables are shown incorrecly when program is built... (3 Replies)
I have an AIX 64-bit program which uses following from AIX5.3
/usr/lib/libc.a(shr_64.o)
/usr/lib/libpthread.a(shr_xpg5_64.o)
/home/jeet_xp/export/power/usr/lib/libsarpc.a(shr.o)
/unix
/usr/lib/libcrypt.a(shr_64.o)
/usr/lib/libc_r.a(shr_64.o)
... (3 Replies)
Hello all,
I'm trying to use gethostbyname_r function with 6 arguments in one of my functions. But the call to this crashes the program. Kindly help me in resolving this...
Compiler Info:
Linux target: i686-hardhat-linux
version: 3.3.1
The following is the piece of code I'm trying to... (1 Reply)
Hi,
Could anyone tell me the reason why the following program crashes?
class A {
int x;
public:
A() {
cout << "from A()" << endl;
}
~A() {
cout << "from ~A()" << endl;
}
};
class B : public A {
public:
B() {
cout << "from B()"... (2 Replies)
I am running openSUSE 11.2 with KDE4.5 on my eMachines e525. I just did a "zypper up" on my system and it reported that Chromium was going to be updated. I agreed and the when the update was finished I shut down Chromium and started it again. It flickered on the screen for a moment and crashed.... (6 Replies)
Production server crashes when there is no traffic on it. Can only recover by going to ALOM and reboot the server. This seems to happen about the same time every month. The only good thing is the server is not in production at the time of the crash.
I have been unable to locate any information in... (5 Replies)
Can someone tell my why every time I try to use 7z it freezes my system? I can't move my mouse, I can't type, I can't kill my xsession. I then restart my system and everything returns to normal. When I try to use 7z my system again freezes. (11 Replies)
Hi,
I am a newbie to linux programming. I have implemented msgqueue in C.
msgrcv() call at the client end is as below:
msgrcv( msgqid, msgptr, msgsize, msgtype, 0 );
My program works fine when msgrcv () from /lib/libc.so.6 is called.
However it crashes when __libc_msgrcv() is called.
... (3 Replies)
I am trying to run apcupsd, but it will not retain contact the UPS
root@meow:/home/ethan/UPS/gapcmon-0.8.9# /etc/init.d/apcupsd start
Starting UPS power management:
A copy of the daemon is still running. If you just stopped it,
please wait about 5 seconds for it to shut down.... (0 Replies)
The Apache server suddenly stops. I am running Debian Jessie
Here are some diagnostics:
root@meow:/var/www# apachectl configtest
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress... (4 Replies)
Discussion started by: Meow613
4 Replies
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qwtcpointerdata
QwtCPointerData(3) Qwt User's Guide QwtCPointerData(3)NAME
QwtCPointerData -
Data class containing two pointers to memory blocks of doubles.
SYNOPSIS
#include <qwt_data.h>
Inherits QwtData.
Public Member Functions
virtual QwtDoubleRect boundingRect () const
virtual QwtData * copy () const
QwtCPointerData & operator= (const QwtCPointerData &)
QwtCPointerData (const double *x, const double *y, size_t size)
virtual size_t size () const
virtual double x (size_t i) const
const double * xData () const
virtual double y (size_t i) const
const double * yData () const
Detailed Description
Data class containing two pointers to memory blocks of doubles.
Constructor & Destructor Documentation
QwtCPointerData::QwtCPointerData (const double *x, const double *y, size_tsize) Constructor
Parameters:
x Array of x values
y Array of y values
size Size of the x and y arrays
Warning:
The programmer must assure that the memory blocks referenced by the pointers remain valid during the lifetime of the QwtPlotCPointer
object.
See also:
QwtPlotCurve::setData(), QwtPlotCurve::setRawData()
Member Function Documentation
QwtDoubleRect QwtCPointerData::boundingRect () const [virtual] Returns the bounding rectangle of the data. If there is no bounding rect, like
for empty data the rectangle is invalid: QwtDoubleRect::isValid() == false
Reimplemented from QwtData.
QwtData * QwtCPointerData::copy () const [virtual] Returns:
Pointer to a copy (virtual copy constructor)
Implements QwtData.
QwtCPointerData & QwtCPointerData::operator= (const QwtCPointerData &data)
Assignment.
size_t QwtCPointerData::size () const [virtual] Returns:
Size of the data set
Implements QwtData.
double QwtCPointerData::x (size_ti) const [virtual] Return the x value of data point i
Parameters:
i Index
Returns:
x X value of data point i
Implements QwtData.
const double * QwtCPointerData::xData () const Returns:
Array of the x-values
double QwtCPointerData::y (size_ti) const [virtual] Return the y value of data point i
Parameters:
i Index
Returns:
y Y value of data point i
Implements QwtData.
const double * QwtCPointerData::yData () const Returns:
Array of the y-values
Author
Generated automatically by Doxygen for Qwt User's Guide from the source code.
Version 5.2.2 Mon Aug 1 2011 QwtCPointerData(3)