基本堆栈中的内存泄漏

我正在研究一个真正简单的堆栈实现，我似乎无法弄清楚为什么我有内存泄漏。 我对代码的期望是在push（）中分配了5个节点，在displayAndDestroy（）中释放了5个节点。 但是Valgrind说我已经分配了6个节点的数据并且只释放了5个。我一直在盯着这个，我不确定我哪里出错了。

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#include  #include  #include  typedef struct STACK{ char data[100]; struct STACK *next; } stack; stack *push( stack *oldTop, char *data ) { stack *newTop = malloc(sizeof(stack)); newTop->next = oldTop; if(!data){ strcpy(newTop->data, newTop->next->data); } else{ strcpy(newTop->data, data); } return( newTop ); } void displayAndDestroy( stack *top ) { stack *currentTop = top; stack *temp; int i=0; while(currentTop){ printf("stack%d: %s\n", i, currentTop->data ); temp = currentTop->next; free(currentTop); currentTop = temp; i++; } } stack *initializer( stack *top, char *fileName ) { char word[100]; char ch; FILE *fr = fopen(fileName, "r"); int i=0; while( (ch=fgetc(fr)) != EOF ){ if( ch == '>' ){ fscanf(fr, "%s\n", word); top = push( top, word ); i++; } } return top; } int main() { stack *top = NULL; top = initializer( top, "testData.txt" ); displayAndDestroy( top ); return 0; } 

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testData.txt

 garbage >stringone >2nd string >s3 moregarbage >THE 4FOURTH4 STRING >5 finalgarbage 

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Valgrind说：

 ==19446== Memcheck, a memory error detector ==19446== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al. ==19446== Using Valgrind-3.10.0.SVN and LibVEX; rerun with -h for copyright info ==19446== Command: ./test ==19446== stack0: 5 stack1: THE stack2: s3 stack3: 2nd stack4: stringone ==19446== ==19446== HEAP SUMMARY: ==19446== in use at exit: 568 bytes in 1 blocks ==19446== total heap usage: 6 allocs, 5 frees, 1,128 bytes allocated ==19446== ==19446== 568 bytes in 1 blocks are still reachable in loss record 1 of 1 ==19446== at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==19446== by 0x4EA544C: __fopen_internal (iofopen.c:73) ==19446== by 0x400880: initializer (test.c:47) ==19446== by 0x400921: main (test.c:65) ==19446== ==19446== LEAK SUMMARY: ==19446== definitely lost: 0 bytes in 0 blocks ==19446== indirectly lost: 0 bytes in 0 blocks ==19446== possibly lost: 0 bytes in 0 blocks ==19446== still reachable: 568 bytes in 1 blocks ==19446== suppressed: 0 bytes in 0 blocks ==19446== ==19446== For counts of detected and suppressed errors, rerun with: -v ==19446== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0) 

Answer 1

您的内存泄漏来自fopen调用，正如您可以从泄漏分配的堆栈跟踪中看到的 – 它来自您调用fopen打开文件（在堆上分配缓冲区结构来管理文件）的事实然后永远不要打电话给fclose 。

读完文件后添加对fclose的调用，它就会消失。