c - 查找C中的内存泄漏

Question

我正在尝试在以下代码中查找内存泄漏。 valgrind 给了我这个:

==14160== 1,850 (592 direct, 1,258 indirect) bytes in 9 blocks are definitely lost in loss    record 2 of 5
==14160==    at 0x4904A06: malloc (vg_replace_malloc.c:149)
==14160==    by 0x405B1F: tsCreate (ticket_set.c:55)
==14160==    by 0x401ECA: test1TS (main.c:62)
==14160==    by 0x40557C: main (main.c:424)

这是函数:

TicketSetStatus tsCreate(TicketSet* t, int n, int c) {
    if(t==NULL){
        return TS_CANNOT_CREATE;
    }
    if (n <= 0){
        return TS_ILLEGAL_PARAMETER;
    }

    t->usedTravels = 0;
    t->originalTravels = n;
    t->cost = c;
    t->moneyLeft = n * c;
    //Date time is array of travels:
    t->dates =  malloc(sizeof(DateTime *)* (n)); //todo maybe c99 allows dynamic arrays?
    for (int i = 0; i < n; i++) {
        t->dates[i] =  malloc(sizeof(char)*GOOD_LENGTH+1);
        if (t->dates[i] == NULL) {
            free(   t->dates);

            return TS_CANNOT_CREATE;
        }
    }

    return TS_SUCCESS;
}

TicketSetStatus tsDestroy(TicketSet* t, int* moneyLeft) {
    if (t == NULL) {
        return TS_FAIL;
    }
    *moneyLeft = (t->cost) * (t->originalTravels-t->usedTravels);

     for (int i = 0; i < t->originalTravels; i++){
        free(t->dates[i]);
    }
    free(t->dates);

    t=NULL; 
    return TS_SUCCESS;
}

当结构是:

struct TS_element {
    int usedTravels;
    int originalTravels;
    int cost;
    DateTime* dates;
    int moneyLeft;
};

和

typedef char* DateType

实际上，使用 free 会使程序崩溃，所以只要程序正常运行，我倾向于忍受内存泄漏。

Answer 1

您如何使用这个 DateTime 数组？如果你稍后再践踏这些值，就会出现泄漏。也许对字符串赋值感到困惑？ 即

char someDateValue[] = "2012-08-15";
t->dates[0] = someDateValue;         // Leak -- your allocated string is lost

相反:

strcpy( t->dates[0], someDateValue );

tsCreate 中的错误情况存在明确的泄漏:

for (int i = 0; i < n; i++) {
    t->dates[i] =  malloc(sizeof(char)*GOOD_LENGTH+1);
    if (t->dates[i] == NULL) {
        free(t->dates);              // Leak -- every element up to i-1 is lost
        return TS_CANNOT_CREATE;
    }
}

在完成 tsCreate 初始化的数据后，您是否正在调用 tsDestroy ？也许您从 main 返回时没有进行清理。

如果这些都没有帮助，您应该发布额外的代码来显示您如何使用数据结构。