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POC++ STL list functions segfaulting with empty list
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  1. POC++ STL list functions segfaulting with empty list
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    copied!<p>I have a list of pointers as a member of a class. I instantiate that class, and various functions such as size() and empty() fail with a segfault when the list is empty. When I add something to the list, they're fine. I tried to abstract what I'm doing with a test file, and it works perfectly. This is what I THINK I'm doing when my code fails (though am clearly not):</p> <pre><code>#include &lt;list&gt; #include &lt;iostream&gt; class Test { int i; }; int main() { std::list&lt;Test*&gt; tlist; if (tlist.empty()) { std::cout &lt;&lt; "List empty"; } else { std::cout &lt;&lt; "List not empty"; } } </code></pre> <p>I can't really post the entire code listing that's causing the issue, as it's fairly large and over a bunch of files, but will try to paste all the relevant bits straight from code:</p> <p>Class declaration in player.h:</p> <pre><code>class Player : public ScreenObject { private: std::list&lt;Thing*&gt; inventory; </code></pre> <p>Nothing is done to that list in the constructor.</p> <p>Where it's failing:</p> <p>main.cpp:</p> <pre><code>Player pc(iname, w_choice, c_choice, 11, 11, WHITE, '@'); </code></pre> <p>....</p> <pre><code>if (pc.addToInv(t)) { currentLevel.delObject(id); } </code></pre> <p>....</p> <p>player.cpp:</p> <pre><code>int Player::addToInv(Thing&amp; t) { if (inventory.size() &lt;= 52) { inventory.push_back(&amp;t); } else { shiplog("Cannot add to inventory, 52 item limit reached",10); return 0; } } </code></pre> <p>The error I get when running it with gdb occurs on the call to size(), and ends up here:</p> <pre><code>Program received signal SIGSEGV, Segmentation fault. 0x0804eda6 in std::_List_const_iterator&lt;Thing*&gt;::operator++ (this=0xbfff9500) at /usr/include/c++/4.4/bits/stl_list.h:223 223 _M_node = _M_node-&gt;_M_next; </code></pre> <p>Any guesses much appreciated!</p> <hr> <p>Full backtrace is:</p> <pre><code>(gdb) bt 0 0x0804e28a in std::_List_const_iterator&lt;Thing*&gt;::operator++ ( this=0xbfff9500) at /usr/include/c++/4.4/bits/stl_list.h:223 1 0x0804e64e in std::__distance&lt;std::_List_const_iterator&lt;Thing*&gt; &gt; ( __first=..., __last=...) at /usr/include/c++/4.4/bits/stl_iterator_base_funcs.h:79 2 0x0804e4d3 in std::distance&lt;std::_List_const_iterator&lt;Thing*&gt; &gt; ( __first=..., __last=...) at /usr/include/c++/4.4/bits/stl_iterator_base_funcs.h:114 3 0x0804e2e6 in std::list&lt;Thing*, std::allocator&lt;Thing*&gt; &gt;::size ( this=0xbffff244) at /usr/include/c++/4.4/bits/stl_list.h:805 4 0x0804df78 in Player::addToInv (this=0xbffff068, t=...) at player.cpp:551 5 0x0804a873 in main (argc=1, argv=0xbffff494) at main.cpp:182 </code></pre>
 

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