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POC++ memory access violation mysteriously goes away if I add one dummy argument to class constructor
 

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  1. POC++ memory access violation mysteriously goes away if I add one dummy argument to class constructor
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    <p>So, lately I've been banging my head on this runtime error I get running this code. This is a client/server application with the client being a DLL injected into another process address space and the server a classical standalone program. This is the incriminated bit of code (I've removed non-relevant parts of the file):</p> <pre><code>#include "TableInfo.h" TableInfo::TableInfo(tstring id) { this-&gt;id = id; } TableInfo::TableInfo(int num, tstring id) { //this-&gt;num = num; this-&gt;id = id; } void TableInfo::dump() { //tcout &lt;&lt; "num = " &lt;&lt; this-&gt;num &lt;&lt; endl; tcout &lt;&lt; "id = " &lt;&lt; this-&gt;id &lt;&lt; endl; } </code></pre> <p>As you can see I've got two constructors but they are pratically the same except for the signature. <code>TableInfo</code> should contains some information that will be later embedded in another object which I'm trying to send from the client to the server over a TPC socket. This is how I do it:</p> <pre><code>TableInfo tt(999, L"MEGAOHM"); // WORKS! //TableInfo tt(L"MEGAHOM2"); // DOESN'T WORK! IpcRequest rr(CBE_NEW_TABLE); rr.setTableInfo(tt); c.sendRq(rr); </code></pre> <p>So, the <code>IpcRequest</code> class is just another class containing one instance of <code>TableInfo</code> and some other variables and it will get sent over to the server. The <code>sendRq</code> function sends the entire object to the server where I try to display the data contained in it. As you can see from the code if I call the 2 arguments constructor it work otherwise I get a memory access violation error. According the to debugger the error occurs in the <code>dump</code> function inside <code>TableInfo</code> when I try to access the id field. I really don't know what this could be related to, of course I can still use a constructor with 2 ore more arguments and the problem disappears but I'd like to know how is this possible.</p> <p>PS: <code>tstring</code> is just a macro I defined which resolves to wstring or string depending on the UNICODE settings.</p>
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    1. USThe Coding Monk
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    1. CODoes `TableInfo` have any `virtual` functions or any base classes with `virtual` functions?
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      1. POC++ memory access violation mysteriously goes away if I add one dummy argument to class constructor
      1. USAdam Rosenfield
    2. COMysterious and nonlogical bugs like this are usually a sign of something wrong with your code that gets optimised away when the planets align in your code. When the planets don't align, the bug gets triggered. Are you compiling with any optimisations on?
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      1. POC++ memory access violation mysteriously goes away if I add one dummy argument to class constructor
      1. USSeth Carnegie
    3. CONo, TableInfo doesn't have any virtual functions. To be honest there isn't a single virtual function in all the code. Also, as far as optimization is concerned, I'm compiling with "standard" Visual Studio 2008 settings, meaning I didn't turn anything ON volutarily. Looking into the "Optimization" tab for the projects everything is labaled as "Default"
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      1. POC++ memory access violation mysteriously goes away if I add one dummy argument to class constructor
      1. USThe Coding Monk
 

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