c - 该函数仅适用于无用的 printf

Question

我通常会越来越努力地解决我在代码中发现的任何错误，但这对我来说完全不合逻辑。它适用于任何字符串和字符分隔符，但仅适用于无用的 printf内while的函数，否则打印

-> Lorem

然后

-> ▼

并随后崩溃。在此先感谢任何可以告诉我发生了什么的人。

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

char **strsep_(char *str, char ch) {
    // Sub-string length
    uint8_t len = 0;
    // The number of sub-strings found means the same as the position where it will be stored in the main pointer
    // Obviously, the number tends to increase over time, and at the end of the algorithm, it means the main pointer length too
    uint8_t pos = 0;
    // Storage for any found sub-strings and one more byte as the pointer is null-terminated
    char **arr = (char**)malloc(sizeof(char **) + 1);
    while (*str) {
        printf("Erase me and it will not work! :)\n");
        if (*str == ch) {
            // The allocated memory should be one step ahead of the current usage
            arr = realloc(arr, sizeof(char **) * pos + 1);
            // Allocates enough memory in the current main pointer position and the '\0' byte
            arr[pos] = malloc(sizeof(char *) * len + 1);
            // Copies the sub-string size (based in the length number) into the previously allocated space
            memcpy(arr[pos], (str - len), len);
            // `-_("")_-k
            arr[pos][len] = '\0';
            len = 0;
            pos++;
        } else {
            len++;
        }
        *str++;
    }
    // Is not needed to reallocate additional memory if no separator character was found
    if (pos > 0) arr = realloc(arr, sizeof(char **) * pos + 1);
    // The last chunk of characters after the last separator character is properly allocated
    arr[pos] = malloc(sizeof(char *) * len + 1);
    memcpy(arr[pos], (str - len), len);
    // To prevent undefined behavior while iterating over the pointer
    arr[++pos] = NULL;

    return arr;
}

void strsep_free_(char **arr) {
    char **aux = arr;
    while (*arr) {
        free(*arr);
        *arr = NULL;
        arr++;
    }
    // One more time to fully deallocate the null-terminated pointer
    free(*arr);
    *arr = NULL;
    arr++;
    // Clearing The pointer itself 
    free(aux);
    aux = NULL;
}

int main(void) {
    char **s = strsep_("Lorem ipsum four words", ' ');
    char **i = s;
    while (*i != NULL) {
        printf("-> %s\n", *i);
        i++;
    }
    strsep_free_(s);
}

Answer 1

崩溃的可能原因很可能是这样的:realloc(arr, sizeof(char **) * pos + 1) .

这与 realloc(arr, (sizeof(char **) * pos) + 1) 相同它没有为您的“数组”分配足够的空间。您需要做的realloc(arr, sizeof(char **) * (pos + 1)) .

与 arr[pos] 的分配相同，您也需要在那里正确使用括号。