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BIG problem with STL List Container

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Join Date: Aug 2006

Posts: 2

Reputation: cgerber is an unknown quantity at this point

Solved Threads: 0

cgerber

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BIG problem with STL List Container

Aug 3rd, 2006

I'm either missing something small or theres a BIG problem somewhere. The following code compiles sucessfully with g++ 4.1.0 under SuSE 10.1 i586 (Linux 2.6.16.13-4-default i686) but it gives a Segmentation Fault when I run it.

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#include <stdio.h>
#include <list>
 
typedef struct    {
    std::list<int> b;
} data;
 
int main(int argc, char **argv)    {
    data *tmp = (data*)malloc(sizeof(data));
 
    printf("Hello1\n");
    tmp->b.push_back(3);
    printf("Hello2\n");
 
    return 0;
}
 
#include <stdio.h>
#include <list>

typedef struct    {
    std::list<int> b;
} data;

int main(int argc, char **argv)    {
    data *tmp = (data*)malloc(sizeof(data));

    printf("Hello1\n");
    tmp->b.push_back(3);
    printf("Hello2\n");

    return 0;
}

Output:
Hello1
Segmentation fault

In fact, any operation on the list (and only the list, everything else works fine, even other members inside the same struct) results in some kind of segmentation fault as if the list needs initialization.

Any help will be appreciated (a lot).

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Join Date: Jul 2006

Posts: 65

Reputation: GloriousEremite will become famous soon enough

Solved Threads: 14

GloriousEremite GloriousEremite is offline

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Re: BIG problem with STL List Container

Aug 3rd, 2006

> as if the list needs initialization.

I'd say that's dead on. If you use malloc the list's constructor isn't going to be called. Since this is C++ you should be using new/delete. You should also avoid using naked pointers most of the time, in favor of smart pointers like std::auto_ptr or a smart pointer provided by the boost library, which will automatically free resources through their destructor

Last edited by GloriousEremite; Aug 3rd, 2006 at 8:12 pm.