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POFinding Reason For Memory Leaking With Char*
 

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  1. POFinding Reason For Memory Leaking With Char*
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    <p>I been working in a project that handles some char* pointers, and it's a requisite of the class to use char* instead of std::string, so...</p> <p>I have this structure definition and this queue: </p> <pre><code>typedef struct packetQueue { char* buf; int length; packetQueue() { buf = new char[]; length = 0; } } PACKET; </code></pre> <p>concurrency::concurrent_queue IP_in_queue;</p> <p>I have this buffer:</p> <pre><code>char sendBuf[MSG_SIZE + sizeof (IP_PACKET_HEADER_T) + 1]; // String to be send </code></pre> <p>and a structure for my new buffer:</p> <pre><code>PACKET ipQueue; </code></pre> <p>then I fill my buffer with this:</p> <pre><code>// Concatenates the header with sended message memcpy(sendBuf, (void*)&amp;sendHeader, sizeof(sendHeader)); memcpy(&amp;sendBuf[sizeof(sendHeader)], readMessage, sendHeader.length); ipQueue.buf = sendBuf; ipQueue.length = packetSize; </code></pre> <p>And then I push my packet to my queue IP_in_queue.push(ipQueue); // Push the buffer in the IP_in_queue</p> <p>This is my loop just in case:</p> <pre><code>while ( 1 ) { // Get the user input cout &lt;&lt; "&gt; "; cin.getline (buf, BUFLEN); IP_PACKET_HEADER_T sendHeader; // Store the header to be send PACKET ipQueue; char* fakeIPAddressDst, *readMessage; delay = atoi(strtok (buf," ")); // Takes the first delay value fakeIPAddressDst = strtok (NULL, " "); // Stores the IP Address readMessage = strtok (NULL, " "); // Stores the sended message Sleep(delay); // Sleep the miliseconds defined // Fills the header with the data neccesary data sendHeader.DIP = inet_addr(fakeIPAddressDst); sendHeader.SIP = inet_addr(initAddress.fakeIpAddress); sendHeader.length = getStringLength(readMessage) + 1; packetSize = sizeof( sendHeader ) + sendHeader.length; // Defines the size of the packet to be send // Concatenates the header with sended message memcpy(sendBuf, (void*)&amp;sendHeader, sizeof(sendHeader)); memcpy(&amp;sendBuf[sizeof(sendHeader)], readMessage, sendHeader.length); ipQueue.buf = sendBuf; ipQueue.length = packetSize; numbytes = packetSize; // The number of bytes of sended buffer char sendedString[BUFLEN + 1]; // Variable for stores the data IP_PACKET_HEADER_T readHeader; // To store the header for showing the information // Print out the content of the packet // Copy from buf to the header memcpy( (void*)&amp;readHeader, ipQueue.buf, sizeof( IP_PACKET_HEADER_T)); // Copy message part memcpy( sendedString, &amp;ipQueue.buf[sizeof(IP_PACKET_HEADER_T)], numbytes - sizeof(IP_PACKET_HEADER_T)); // Append \0 to the end sendedString[numbytes - sizeof(IP_PACKET_HEADER_T)] = '\0'; // Save the IP information of the packet in a struct for print on the screen struct in_addr fakeAddrHost; fakeAddrHost.s_addr = readHeader.SIP; // Print the neccesary data cout &lt;&lt; "[IN] DST: " &lt;&lt; fakeIPAddressDst &lt;&lt; endl; // Fake IP address of the destination cout &lt;&lt; "[IN] SRC: " &lt;&lt; inet_ntoa(fakeAddrHost) &lt;&lt; endl; // Fake IP address of the host cout &lt;&lt; "[IN] MSG: " &lt;&lt; sendedString &lt;&lt; endl ; // Message to send IP_in_queue.push(ipQueue); // Push the buffer in the IP_in_queue } </code></pre> <p>I know there is a memory leak in this procedure but I'm not sure. When I push my packet, the buf pointer keeps pointing to my sendBuf, am I right? Because the assignment does that, but if I delete my pointer in the ipQueue after I push the program crashes. I have to say, after I push that struct into the queue, another thread try to pop that one, and obviously if I delete my ipQueue pointer I'll lost my buffer, so how can I avoid this memory leak?</p> <p>Thanks</p> <p>EDIT:</p> <p>The memory leak using the definition of buf = nullptr</p> <pre><code>---------- Block 1 at 0x0068BB30: 264 bytes ---------- Call Stack: d:\program files (x86)\microsoft visual studio 11.0\vc\include\concurrent_queue.h (402): Host.exe!Concurrency::concurrent_queue&lt;packetQueue,std::allocator&lt;packetQueue&gt; &gt;::_Allocate_page + 0xF bytes f:\dd\vctools\crt_bld\self_x86\crt\src\concurrent_queue.cpp (113): MSVCP110D.dll!Concurrency::details::_Micro_queue::_Push + 0xD bytes f:\dd\vctools\crt_bld\self_x86\crt\src\concurrent_queue.cpp (232): MSVCP110D.dll!Concurrency::details::_Concurrent_queue_base_v4::_Internal_push d:\program files (x86)\microsoft visual studio 11.0\vc\include\concurrent_queue.h (566): Host.exe!Concurrency::concurrent_queue&lt;packetQueue,std::allocator&lt;packetQueue&gt; &gt;::push + 0xF bytes d:\users\silex rpr\documents\visual studio 2012\projects\project2\project2\host.cpp (802): Host.exe!main f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c (536): Host.exe!__tmainCRTStartup + 0x19 bytes f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c (377): Host.exe!mainCRTStartup 0x7662339A (File and line number not available): kernel32.dll!BaseThreadInitThunk + 0x12 bytes 0x77179EF2 (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0x63 bytes 0x77179EC5 (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0x36 bytes </code></pre>
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    1. USoscar.rpr
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    1. COWoah... you have quite a messy mixture of C and C++ in that...
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      1. POFinding Reason For Memory Leaking With Char*
      1. USMysticial
    2. COThis isn't C, you're using a C++ compiler. structures in C cannot have methods and constructors
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      1. POFinding Reason For Memory Leaking With Char*
      1. USEd S.
    3. COYeah, I'm sorry I thought that I put my tag right, sorry again
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      1. POFinding Reason For Memory Leaking With Char*
      1. USoscar.rpr
 

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