使用 "Free()" 命令后程序崩溃 (C)

Question

我有以下结构：

typedef struct employee
{
    int   name_length;
    char* name;
    float  salary;
} Employee;

以及以下函数：

Employee** makeArr(char* fileName, int* size)
{
    FILE* f = fopen(fileName, "rb");
    checkOpenFile(f);
    Employee** arr = (Employee**)malloc(sizeof(Employee*));
    checkAllocation(&arr);
    int counter = 0;
    while (!feof(f))
    {
        
        int employeeNameSize;
        float employeeSalary;
        fread(&employeeNameSize, sizeof(int), 1, f);
        if (feof(f))
            break;
        char* employeeName = (char*)malloc(sizeof(char) * employeeNameSize+1);
        checkAllocation(&employeeName);
        fread(employeeName, sizeof(char), employeeNameSize, f);
        employeeName[employeeNameSize] = '[=12=]';
        fread(&employeeSalary, sizeof(float), 1, f);
        arr[counter] = makeEmployee(employeeNameSize, employeeName, employeeSalary);
        counter++;
        realloc(arr, sizeof(Employee*)*(counter));
    }
    *size = counter;
    fclose(f);
    return arr;
}

和：

void freeEmployeeArr(Employee** arr, int size)
{
    for(int i = 0; i < size; i++)
    {
        free(arr[i]->name);
        free(arr[i]);
    }
     free(arr); 
}

还有这个：

Employee* makeEmployee(int nameLength, char* name, float salary)
{
    Employee* tmp = (Employee*)malloc(sizeof(Employee));
    checkAllocation(&tmp);
    tmp->name_length = nameLength;
    tmp->name = name;
    tmp->salary = salary;
    return tmp;

}

我的主要：

void main(int argc, char* argv[])
{
    char* name1 = argv[1]; 
    char* name2 = argv[2];
    int size;
    Employee** ans = makeArr(name1, &size);
    freeEmployeeArr(ans, size);
}

我遇到的问题：

free(arr);

使我的程序崩溃。如果我删除这一行，一切正常。但这个具体问题给我带来了一些问题。如果我试图在不调试的情况下开始，我会收到以下消息：

如果我正在调试，我会收到以下消息：

我真的不知道我的程序出了什么问题。我读到当我 realloc/malloc 的值为零时可能会出现此类问题。但事实并非如此。

任何人都可以在这里发现我的错误吗？提前致谢。

Answer 1

行

realloc(arr, sizeof(Employee*)*(counter));

不好。您必须将返回的新指针分配给 arr.

应该是这样的：

Employee** newArr = realloc(arr, sizeof(Employee*)*(counter));
if (newArr == NULL) {
    /* handle error, clean up and return from the function */
}
arr = newArr;

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