m_gradient() constructor is called to construct m_gradient, which in turns sets a variable called m_S to NULL(0), then in the assignment operator, because the m_S is NULL, Visual Studio throws an exception saying that destination pointer is null, but it's not fatal. I don't like that to happen because I have to press ignore many many times when the program is debugged, how can I fix this bug (not mine) to avoid the null destination pointer exception?
As an intermediate layer, the function calls boost unbounded array operator = which in turns calls std::copy which results in this error
When I try to run this, I only get the message "Material pointer is null". So, somehow the pointer is null after the hitObjects-function is called, even though it isn't inside that function.
So I'm writing a small program for class, and for some reason I keep getting an error when trying to initialize head to NULL. Even threw in the namespace just to see, nothin'.
#ifndef NUMBERLIST_H #define NUMBERLIST_H using namespace std;
[Code].....
There's my header file. Not sure what I'm doing wrong with the constructor.
EDIT: Got it to work with nullptr, but still curious why that isn't working
In jumping into C++ it says something like this: It's not necessary but when you delete a pointer it's a good idea to reset it as a null pointer. That if your code try's to dereference the pointer after being freed, your program will crash. This happens to a lot of experienced programmers.
This could corrupt users data. delete p_int; p_int = NULL;
1. If you can deference a pointer after the memory is freed, why can't you just delete the pointer?
2. If you can do 1, how do you delete the pointer using code?
3. Every thing I've read says that free memory is handed out in a sequenced order. I don't believe that is true at all. I may be wrong. Why can't you put the data in any number of places if it will fit. Isn't the compiler smart enough to know where bytes (bits)and pieces are stored?
4. If you storing anything in free memory must use a pointer to it?
5. Can a pointer or something similar be used with stack memory?
in the below program for both class pointers pointing to null. Class contains normal function executing but class contains virtual function getting segmentation fault.
lets say I have a pointer p_unit of type c_unit* (c_unit is an a.b.c.)
I have a function that returns a pointer to a new c_unit object:
c_unit * man_add_unit() { c_unit * local_p_unit; unsigned short int local_run_code; print_man_add_menu(); local_run_code = get_a_run_code(); // this bit just gets user input switch (local_run_code)
[code]....
I assign that to p_unit, then add it to a vector v_units:
p_unit = man_add_unit(); v_units.push_back(p_unit); cout << "New unit added. ";
The whole program runs on a loop, and another thing the user can do is to print out data on c_unit objects pointed to by v_units. The problem is, in that function up there ^ I give the user the option to go back to main menu without creating a unit.
Since "local_p_unit" is declared but not assigned an initial value, I'm guessing the function would return a "null" pointer (which is what's hanging me up). If I just let this run with the above code, and go to print out the unit data, the program crashes.
I tried to make an if thing with p_unit == 0 but this always returns false and doesn't catch the "bad" unit that will subsequently cause a crash.
Btw, I have considered assigning a reference to a generic c_unit object to that there local_p_unit so it won't return null, then remove pointers to that object from v_units at the end of the loop.. But I know there's got to be a better way.
struct mystruct{ int n; }; class mscope{ public: std::vector<mystruct> mv;
[Code] .....
So I have a vector of structs and I want to traverse it, find a struct that matches a constraint and obtain a pointer to that struct. I made a function for this purpose which takes a number and an empty pointer that will store the reference. However, after function returns the pointer becomes null. What could be causing this?
getting an invalid null pointer error message after a successful build. This program is supposed to ask for firstName, lastName, age and maJor and keep doing so until the age that is input is 0 and then the program closes. Here is what I have.
#include <iostream> #include <string> using namespace std;
I have two basic questions about what is happening:
1. The return value of ret_con should be pointing to const, but instead it's pointing to a (non-const) pointer to const. Does the compiler only check the qualifiers of the end destination, why doesn't this give a warning?
2. The original variable from ret_con (ci) is a local automatic, shouldn't its lifetime have expired when you leave the scope?
I also checked this with C++ compiler (taking out the auto keyword), it gave no warnings either.
I want to examine every packet of a pcap trace file and if packet n+1 source address == packet n destination address && packet n+1 destination address == packet n source address i want to get the time between those 2 packages.
Problem: I can't compare the ipv6 adresses of src and destination.
comparing src and src is no problem. dst with dst as well
if i try to compare these adresses i will never get a match. But i use a trace file with much matches. Do i need a offset in pkt_ptr? I saw some examples which deals with it.
Code:
uint32_t* test = (uint32_t*)ipv6_dst; for (uint32_t j=0;j<sizeof(ip_hdr->ip6_dst);j++) { printf ("%x", *(test+j)); } printf ("
I am looking at one of the functions of an exercise:
void escape(char * s, char * t) { int i, j; i = j = 0; while ( t[i] ) { /* Translate the special character, if we have one */ switch( t[i] ) {
[code]...
Notice the while loop evaluates the current value in t to true or false. When we hit the null terminator, does that get evaluated as 0 and hence evaluates as a falsy value so the while loop exits?
When you login to my site my loginservice which is done by ajax and json make a session called context.Session["Name"]. With BreakPoints it shows that everything is good and the variables are in place. However when I use Session["Name"] it comes out as null.
I will add my code at the bottem not
using System; using System.Collections.Generic; using System.Linq;
I catch an exception and want to log it on the console. This works as exepcted, but Valgrind shows me a set of invalid reads.
Here the code of the catch-block:
} catch(HGL::IOException &e) { logError(e); }
The signature of the logDebug is: BasicLogger &operator<<(const std::exception &e);
Now valgrind shows me 4 errors like that:
==20943== Invalid read of size 1 ==20943== at 0x402C658: strlen (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so) ==20943== by 0x41554DD: std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& std::operator<< <wchar_t, std::char_traits<wchar_t> >(std::basic_ostream<wchar_t, std::char_traits<wchar_t> >&, char const*) (in /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16)
[Code] .....
Generally I dislike invalid read in my code, even if they are harmless like in that case.
If I don't pass a reference, but a copy of the exception, I don't get this invalid reads, but also loose all information, because of the implicit upcasting.
Why I get the illegal read, resp. why std::wstring is deleting it on the way to the <<-operator?
I'm trying to do some operator overloading, the function is supposed to add the values at index [i] of two vectors and place the result in the returning vector. The problem is I keep getting a vector out of range. This is the overloaded operator I'm working with (relatively new to these):
vector<float> operator+(const vector<float>& a, const vector<float>& b){ unsigned long size; vector<float> temp; if(a.size() >= b.size()) size = a.size();
[Code] .....
and then I would do something like this in the main:
vector<float> v, v1, v2;
v1.push_back(9.1); ... v2.push_back(8); ... v = v1 + v2;
but when I try to output the vector v I just get a vector out of range exception.
I'm making an "improved" array for my programing class. It's currently unfinished, so you might see some commented out code. I'm trying to debug what I have.
I keep getting these errors when I try to complile my main.cpp:
In file included from main.cpp:3:0:
array.h:107:43: error: expected type-specifier before ‘out_of_range’ array.h:107:43: error: expected ‘)’ before ‘out_of_range’ array.h:107:43: error: expected initializer before ‘out_of_range’ array.h:121:55: error: expected type-specifier before ‘out_of_range’ array.h:121:55: error: expected ‘)’ before ‘out_of_range’ array.h:121:55: error: expected initializer before ‘out_of_range’
My main file:
#include <iostream> #include <stdexcept> #include "array.h" using namespace std; using namespace ArrayNameSpace; int main() { Array<int> testSubject(5); return 0; }//End main
aannnd my Array.h file:
//ADD CONSTS TO METHODS //CURRENTLY WORKING ON EXCEPTIONS AND BRACKET[] OVERLOADS. I HAVE TO FIGURE OUT SOLUTIONS FOR REACHING //INDEXES FOR CHARS AND ENUMS #ifndef __array_H__ #define __array_H__ #include <stdexcept> namespace ArrayNameSpace {
I have been assigned to create a search function in text file, but I received this error when I run the program and try to search: Error message: Unhandled exception at 0x0f85d442 (msvcr100d.dll) in Ticket.exe: 0xC0000005: Access violation reading location 0xcccccd08.
I don't know what is the exactly problem. So I just copy everything and paste here. Please don't fear of these codes, I have 2 files only, but I will paste 3 files here, the one is prototypes.h, then the main.cpp, the last one is part of my function that can working well alone, but when I put them into main.cpp I will get the error message like I mentioned before.
write a program as described below: program that reads in two integers (age, social security number). You should write functions that throw an out-of-range exception forage (no negative numbers)SSN (must be a 9-digit integer) My code is written below:
#include "std_lib_facilities_4.h" int main(){ int age = 0; int ssn = 0;
If a class A contains an array of objects of another class B.. And in the constructor of A, while constructing objects of B, any one object throws an exception, then how can we guarantee to release all the memory acquired.. so that there is no memory leak..
class B{}; class A{ public: B Array[100]; ... };
In the above code, if in constructor of A, suppose 99 objects of B are constructed successfully, but 100th object throws exception, then how can we guarantee to release all the memory acquired by the other 99 objects?
I have one problem deleting a file with boost. The file is opened in another application and cannot be deleted. I am supposed to received an exception error but I don't get it.
I have put a breakpoint inside the catch part but it does not come to this point. Instead, the the output window of visual studio, I got these lines:
First-chance exception at 0x00007FFD2E575A88 in site_server.exe: Microsoft C++ exception: boost::filesystem::filesystem_error at memory location 0x00000070F8E3E920. Unhandled exception at at 0x00007FFD2E575A88 in site_server.exe: Microsoft C++ exception: boost::filesystem::filesystem_error at memory location 0x00000070F8E3E920.
It is advisable not to throw the exception from destructor. Because if exception happens stack unwinding happens. suppose the destructor again throws the exception then on part of first exception again one exception is thrown and exceptions can not be handled at same time. This is what i read from stack over flow.
