通過C中的函數更改動態2D char數組？

Question

我正在創建此示例運行，以便可以更好地理解如何通過其他函數編輯動態數組，但是一旦添加了輔助函數，我便開始遇到段錯誤。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void other_side(char ***funk);

int main()
{
    int i;
    char *argv[11] = {"fish", "dish", "lags", "fags", "shag", "cool", "bean", "rekt", "noon", "coon", "lolz"};

    char **yep, **nop;
    yep = malloc(10 * sizeof *yep);
    if(!yep) { // <-----------------added check for malloc error
        printf("Error: failure to allocate memory\n");
        exit(1);
    }

    printf("10 times %lu\n\n", sizeof *yep);
    for(i = 0; i<10; i++) {
        yep[i] = strdup(argv[i]);
        printf("%s is in yep.\n", *(yep+i)); 
    }
    nop = realloc(yep, 11 * sizeof *yep); //you reallocate to the new total size.
    if(nop == NULL) {
        printf("Error: failure to allocate memory\n")
        exit(1);
    }
    yep = nop;
    *(yep+10) = strdup(argv[10]); 
    printf("Last but certainly not least, %s is in yep.\n", *(yep+10));

    printf("Now to send yep over to the other side and have its values changed.\n");

    other_side(&yep);

    printf("Did it change?\n\n");

    for(i=0; i<11; i++)
        printf("%s is in yep.\n", *(yep+i));

    for(i=0; i<11; i++) { //issue fixed when added strdup() above, previously static
        free(*(yep+i)); 
    }
    free(yep);
    return 0;
}

void other_side(char ***funk)
{
    char *arr[11] = {"dude","yeah","gnar","nice","epic","need","more", "word","four","this","test"};
    int i;
    for(i=0; i<11; i++) {
        **(funk+i) = strdup(arr[i]); //added strdup() here as well
        printf("%s is currently in yep.\n", **(funk+i));
    }
    printf("\n");
}

我注意到的幾件事是，當我嘗試將main的第11個內存塊釋放到數組中時，Valgrind注意到了不必要的釋放。 我不確定這是否是我的問題，但我也注意到該函數只會在導致分段錯誤之前更改兩個單詞。

編輯說明：自編輯以來，我仍然遇到段錯誤，但是valgrind對正在發生的事情更加清楚。 （對位於地址0x400B18的映射區域的錯誤權限）

Answer 1

您關於運算符的優先順序很重要，並且您錯過了兩個括號以確保操作正確。 這： **(funk+i)意思是： *(funk[i]) ，而不是您想要的(*funk)[i] 。

這個：

**(funk+i) = strdup(arr[i]);
printf("%s is currently in yep.\n", **(funk+i));

應該是這樣的：

*((*funk)+i) = strdup(arr[i]);
printf("%s is currently in yep.\n", *((*funk)+i));

坦率地說，它很容易理解為：

(*funk)[i] = strdup(arr[i]);
printf("%s is currently in yep.\n", (*funk)[i]);

我將其余的內存管理留給您解決。 （即，您在上述循環代碼中覆蓋的所有指針所指向的動態內存泄漏）。