在堆摘要错误中不匹配 [英] Mismatched in Heap summary error

问题描述

我知道我不需要担心静态可达字节，但是这种情况是不同的。

I know I do not need to worry about the Still reachable bytes, but this case is different.

我的文件：
wscramble_fio.cpp

My files: wscramble_fio.cpp

// wscramble.cpp
// Word Scramble guessing game
// Illustrates string library functions, character arrays,
// arrays of pointers, etc.
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <string>
#include <fstream>

using namespace std;

// Prototype
void permute(char items[], int len);

// Define an array of strings (since a string is just a char array)
// and since string are just char *'s, we really want an array of char *'s


int main(int argc, char * argv[])
{
  if (argc != 2)
  {
    cout << "Usage : " << argv[0] << "<wordbankFile>" << endl ;
    return -1 ;
  }

  ifstream inputFile ;
  inputFile.open(argv[1]);

  if (!inputFile.is_open())
  {
    cout << "Error opening file : " << argv[1] << endl ;
    return -1 ;
  }

  int wordCount = 0 ;

  inputFile >> wordCount ;
  if (inputFile.fail())
  {
    cout << "File format incorrect" << endl ;
    return -1 ;
  }

  // Ignore the \n following the number.
  //inputFile.ignore(1024, '\n') ;

  char ** wordBank = new char* [wordCount] ;
  char buffer[41] ;
  int i = 0 ;
  while (!inputFile.eof())
  {
    inputFile >> buffer ;
    //cout << buffer ;
    if (strcmp(buffer,"\n") == 0 || strcmp(buffer," ") == 0 || strcmp(buffer, "") == 0)
    {
      continue ;
    }

    if (i >= wordCount)
    {
      cout << "Too many words in the file" << endl ;
      inputFile.close() ;
      return -1 ;
    }
    wordBank[i] = new char [strlen(buffer)+1] ;
    strcpy(wordBank[i],buffer) ;
    buffer[0] = '\0' ;
    i++ ;
  }

  for (int i = 0 ; i < wordCount ;i++)
  {
    cout << wordBank[i] << endl ;
  }

  srand(time(0));
  char guess[80];

  bool wordGuessed = false;
  int numTurns = 10;

  // Pick a random word from the wordBank
  int target = rand() % wordCount;
  int targetLen = strlen(wordBank[target]);

  // More initialization code
  char* word = new char[targetLen+1];
  strcpy(word, wordBank[target]);
  permute(word, targetLen);

  // An individual game continues until a word
  // is guessed correctly or 10 turns have elapsed
  while ( !wordGuessed && numTurns > 0 ){
    cout << "\nCurrent word: " << word << endl;
    cin >> guess;
    wordGuessed = (strncmp(guess, wordBank[target], targetLen+1) == 0);
    numTurns--;
  }
  if(wordGuessed){
    cout << "You win!" << endl;
  }
  else {
    cout << "Too many turns...You lose!" << endl;
  }


  /* This would go at the end of program. For now i m just writing here */
  for (int i = 0 ; i < wordCount ; i++)
  delete (wordBank[i]) ;
  delete [] wordBank ;
  inputFile.close() ;
}

// Scramble the letters
void permute(char items[], int len)
{
  for(int i=len-1; i > 0; --i){
    int r = rand() % i;
    int temp = items[i];
    items[i] = items[r];
    items[r] = temp;
  }

}

wordbank.txt

wordbank.txt

6 
cs103 trojan
midterm 
aced 
perfect 
score

当我使用命令：

valgrind --tool=memcheck --leak-check=yes ./wscramble_fio wordbank.txt

$ b b

valgrind命令导致以下输出。

The valgrind command results in the following output.

     ==10409== Mismatched free() / delete / delete []
==10409==    at 0x4C2BADC: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==10409==    by 0x4015D7: main (in /home/simpleguy/CCPP/wscramble_fio)
==10409==  Address 0x5a1c550 is 0 bytes inside a block of size 5 alloc'd
==10409==    at 0x4C2AFE7: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==10409==    by 0x401489: main (in /home/simpleguy/CCPP/wscramble_fio)
==10409== 
==10409== Mismatched free() / delete / delete []
==10409==    at 0x4C2BADC: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==10409==    by 0x401608: main (in /home/simpleguy/CCPP/wscramble_fio)
==10409==  Address 0x5a1c370 is 0 bytes inside a block of size 6 alloc'd
==10409==    at 0x4C2AFE7: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==10409==    by 0x40135D: main (in /home/simpleguy/CCPP/wscramble_fio)
==10409== 
==10409== 
==10409== HEAP SUMMARY:
==10409==     in use at exit: 0 bytes in 0 blocks
==10409==   total heap usage: 10 allocs, 10 frees, 8,853 bytes allocated
==10409== 
==10409== All heap blocks were freed -- no leaks are possible
==10409== 
==10409== For counts of detected and suppressed errors, rerun with: -v
==10409== ERROR SUMMARY: 7 errors from 2 contexts (suppressed: 2 from 2)

推荐答案

您应该使用选项--leak-check = full --show-reachable = yes重新运行valgrind下的程序，以获取泄漏的完整堆栈跟踪。这在上述报告中由Valgrind建议。

You should rerun your program under valgrind using the option "--leak-check=full --show-reachable=yes" to get the complete stack trace where you are leaking. This is suggested by the Valgrind in the above report.

$ valgrind --tool = memcheck --leak-check = full --show-reachable = yes ./wscramble_fio wordbank.txt

$ valgrind --tool=memcheck --leak-check=full --show-reachable=yes ./wscramble_fio wordbank.txt

如果您希望在Valgrind检测到泄漏时由调试器附加，以便您可以进行实时调试，则应使用以下命令：

If you want to attach by the debugger whenever leak is detected by the Valgrind so that you can do live debugging, you should use the following command:

$ valgrind --tool = memcheck --leak-check = yes --db-attach = yes ./wscramble_fio wordbank.txt

$ valgrind --tool=memcheck --leak-check=yes --db-attach=yes ./wscramble_fio wordbank.txt

通过这种方式，每当valgrind遇到错误时，你的程序就会被GDB自动附加。

By this way, your program would automatically be attached by GDB whenever error encounter by valgrind.

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