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POHeap Corruption in release mode only
 

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  1. POHeap Corruption in release mode only
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    <p>This is a printing thread that prints the statistic of my currently running program</p> <pre><code>void StatThread::PrintStat(){ clock_t now = 0; UINT64 oneMega = 1&lt;&lt;20; const char* CUnique = 0;; const char* CInserted = 0;; while((BytesInserted&lt;=fileSize.QuadPart)&amp;&amp;flag){ Sleep(1000); now = clock(); CUnique = FormatNumber(nUnique); CInserted = FormatNumber(nInserted); printf("[ %.2f%%] %u / %u dup %.2f%% @ %.2fM/s %.2fMB/s %3.2f%% %uMB\n", (double)BytesInserted*100/(fileSize.QuadPart), nUnique,nInserted,(nInserted-nUnique)*100/(double)nInserted, ((double)nInserted/1000000)/((now - start)/(double)CLOCKS_PER_SEC), ((double)BytesInserted/oneMega)/((now - start)/(double)CLOCKS_PER_SEC), cpu.GetCpuUtilization(NULL),cpu.GetProcessRAMUsage (true)); if(BytesInserted==fileSize.QuadPart) flag=false; } delete[] CUnique; //would have worked with memory leak if commented out delete[] CInserted; // crash at here! heap corruption } </code></pre> <p>This is FormatNumber that returns a pointer to a char array</p> <pre><code>const char* StatThread::FormatNumber(const UINT64&amp; number) const{ char* result = new char[100]; result[0]='\0'; _i64toa_s(number,result,100,10); DWORD nDigits = ceil(log10((double)number)); result[nDigits] = '\0'; if(nDigits&gt;3){ DWORD nComma=0; if(nDigits%3==0) nComma = (nDigits/3) -1; else nComma = nDigits/3; char* newResult = new char[nComma+nDigits+1]; newResult[nComma+nDigits]='\0'; for(DWORD i=1;i&lt;=nComma+1;i++){ memcpy(newResult+strlen(newResult)-i*3-(i-1),result+strlen(result)-i*3,3); if(i!=nComma+1){ *(newResult+strlen(newResult)-4*i) = ','; } } delete[] result; return newResult; } return result; } </code></pre> <p>What is really weird was that it crashed only in release mode because of a heap corruption, but run smoothly in debug mode. I've already checked everywhere and found no obvious memory leaks, and even Memory Leak Detector said so too.</p> <pre><code>Visual Leak Detector Version 2.2.3 installed. The thread 0x958 has exited with code 0 (0x0). No memory leaks detected. Visual Leak Detector is now exiting. The program '[5232] Caching.exe' has exited with code 0 (0x0). </code></pre> <p>However, when run in release mode,it threw an error that said my program stop working and I clicked on debug, it pointed to the line that caused the heap corruption. </p> <pre><code>The thread 0xe4c has exited with code 0 (0x0). Unhandled exception at 0x00000000770E6AE2 (ntdll.dll) in Caching.exe: 0xC0000374: A heap has been corrupted (parameters: 0x000000007715D430). </code></pre> <p>If I commented out this line, it worked fine but Memory Leak Detector would have complained about memory leak! I don't understand how to cause a heap corruption when there was no memory leaks, (at least that's what the Leak Detector said). Please help, Thank you in advance.</p> <p>Edit: Heap corruption was fixed, because in the very last iteration, I still copied 3 byes to the front instead of whatever is leftover. Thank you all for helps!</p> <pre><code>const char* StatThread::FormatNumber(const UINT64&amp; number) const{ char* result = new char[100]; result[0]='\0'; _ui64toa_s(number,result,100,10); DWORD nDigits = (DWORD)ceil(log10((double)number)); if(number%10==0){ nDigits++; } result[nDigits] = '\0'; if(nDigits&gt;3){ DWORD nComma=0; if(nDigits%3==0) nComma = (nDigits/3) -1; else nComma = nDigits/3; char* newResult = new char[nComma+nDigits+1]; DWORD lenNewResult = nComma+nDigits; DWORD lenResult = nDigits; for(DWORD i=1;i&lt;=nComma+1;i++){ if(i!=nComma+1){ memcpy(newResult+lenNewResult-4*i+1,result+lenResult-3*i,3); *(newResult+lenNewResult-4*i) = ','; } else{ memcpy(newResult,result,lenNewResult-4*(i-1)); } } newResult[nComma+nDigits] = '\0'; delete[] result; return newResult; } return result; } </code></pre>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCong Hui
    1. USCong Hui
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    2. PO
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    3. PO
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    1. This table or related slice is empty.
    1. COThis is a really silly way to add commas to a number. Firstly, the `nDigits > 3` check for an unsigned number can just be done using `number > 999`. Once you have the number as a string, just work from right to left, copying the text and inserting a comma every three digits. Copy it this way to the tail of the buffer. When done do a `memmmove` to move the string to the beginning of the buffer. 100 bytes is enough to do this all in one buffer for a 64 bit integer.
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      1. POHeap Corruption in release mode only
      1. USKaz
    2. COThank you for the thought, I will try it out later
      singulars
      1. POHeap Corruption in release mode only
      1. USCong Hui
 

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