Question

我正在C项目中工作，我对C很新，所以这可能是一个非常简单的答案，但我无法找到如何解决这个问题。

我所拥有的是以下列方式在头文件中定义的结构。

typedef struct CallLogSearchDataStruct
{
    char * date;
    char * time;
    char * bParty;
    char * aParty;
    float duration;
    char * cleardownCause;
    struct CallLogSearchOutboundStruct * outboundLegs;
} callLogSearchDataStruct;

然后使用以下代码片段对其进行引用和分配。

callLogSearchDataStruct * callLogSearchData = NULL;

callLogSearchData = (callLogSearchDataStruct*)calloc(INITIAL_CALL_STRUCT_SIZE,sizeof(callLogSearchDataStruct));

INITIAL_CALL_STRUCT_SIZE设置为100。

我有一些代码在while循环中循环，这会增加一个名为currentStructIndexValue的变量。每次增加此值时，我都会调用一个名为reallocateStructures的函数。这包含各种参数，例如我想重新分配的结构数组。

即。应该发生什么，callLogSearchDataStructure被调用为100的大小。当currentStructIndexValue值变为101并且调用reallocateStructures函数时，结构应该调整大小以包含另一个100，即现在包含200.

以下是我遇到问题的reallocateStructures函数的代码。

int reallocateStructures(callLogSearchResultStruct **callLogSearch, callLogSearchDataStruct ** callLogSearchData, 
        switchIDStructure ** switches, int *timesStructHasBeenReallocated, int currentStructIndexValue,
        int dataRow)
{
    int INITIAL_CALL_STRUCT_SIZE = 100;
    int currentSize = 0;
    int newSize = 0;
    int initFromIndex = 0;

    if (currentStructIndexValue == INITIAL_CALL_STRUCT_SIZE) {
        printf("REALLOCATING STRUCTURES");
        currentSize = currentStructIndexValue * *timesStructHasBeenReallocated;

        newSize = currentSize + INITIAL_CALL_STRUCT_SIZE;
        *timesStructHasBeenReallocated = *timesStructHasBeenReallocated + 1;

        callLogSearchData = (callLogSearchDataStruct*) realloc(callLogSearchData, newSize * sizeof (callLogSearchDataStruct));
        callLogSearch = (callLogSearchResultStruct*) realloc(callLogSearch, newSize * sizeof (callLogSearchResultStruct));
        switches = (switchIDStructure*) realloc(switches, newSize * sizeof (switchIDStructure));

        for (initFromIndex = currentSize; initFromIndex < newSize; initFromIndex++) {
            callLogSearchData[initFromIndex]->aParty = NULL;
            callLogSearchData[initFromIndex]->bParty = NULL;
            callLogSearchData[initFromIndex]->cleardownCause = NULL;
            callLogSearchData[initFromIndex]->date = NULL;
            callLogSearchData[initFromIndex]->duration = 0;
            callLogSearchData[initFromIndex]->outboundLegs = NULL;
            callLogSearchData[initFromIndex]->time = NULL;

            callLogSearch[initFromIndex]->date = NULL;
            callLogSearch[initFromIndex]->dRowIndex = dataRow;

            switches[initFromIndex]->switchID = NULL;
        }
        return 0;
    }
    return 1;
}

以下是我如何调用上述方法

if (reallocateStructures(&callLogSearch, &callLogSearchData, &switches, &timesStructHasBeenReallocated, currentStructIndexValue, dataRow) == 0)
{
   //Structures have been reallocated so reset the index
   currentStructIndexValue = 0;
}

我已经逐步完成了GDB中的代码，发现currentSize，newSize变量是正确的，即当前大小为100，新大小将为200，但是当它执行第一次重新分配时对于callLogSearchData，我的应用程序崩溃了以下GDB消息

*** glibc detected *** realloc(): invalid size: 0xbfffed18 ***
*** glibc detected *** realloc(): invalid pointer: 0xbfffed1c ***
*** glibc detected *** realloc(): invalid pointer: 0xbfffed14 ***

感谢您提供的任何帮助。

Answer 1

在reallocateStructures函数中，为每个项目传递一个指向指针的指针。当你调用realloc()时，你应该使用指针到指针来获得原始指针，既可以输入参数，也可以在分配结果时使用。换句话说，您目前拥有：

   callLogSearchData = (callLogSearchDataStruct*) realloc(callLogSearchData, newSize * sizeof (callLogSearchDataStruct));

你想：

   *callLogSearchData = (callLogSearchDataStruct*) realloc(*callLogSearchData, newSize * sizeof (callLogSearchDataStruct));

Answer 2

        callLogSearchData = (callLogSearchDataStruct*) realloc(callLogSearchData, newSize * sizeof (callLogSearchDataStruct));
        callLogSearch = (callLogSearchResultStruct*) realloc(callLogSearch, newSize * sizeof (callLogSearchResultStruct));
        switches = (switchIDStructure*) realloc(switches, newSize * sizeof (switchIDStructure));

上述赋值的左侧是您尝试分配单个指针的双指针。您还可以使用双指针来访问结构的内容。

重新分配内存会导致下一个大小无效

2 个答案: