我正在用C写一个函数来加载一个文件作为一个二维数组(char **
),问题是根据Valgrind我有内存泄漏,你能帮助我吗?
我给你提供了一个完整的例子,可以复制。而且,我的学校只允许我某些函数来执行这个任务:open
、fopen
、close
、fclose
、malloc
、free
、getline
、lseek
...(不允许我使用stat
)。
我也可以使用我自己的realloc
实现。
我的代码:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
void my_free_word_array(char **word_array)
{
size_t i = 0;
if (!word_array) {
return;
}
while (word_array[i] != NULL) {
free(word_array[i]);
++i;
}
free(word_array);
}
char **append_word_array(char **array, char *line)
{
size_t array_len = 0;
while (array[array_len])
array_len++;
size_t len = strlen(line);
if (line[len - 1] == '\n')
line[len - 1] = '\0';
char **new_array = malloc(sizeof(char *) * (array_len + 2));
for (size_t i = 0; i < array_len; i++)
new_array[i] = array[i];
new_array[array_len] = strdup(line);
new_array[array_len + 1] = NULL;
free(array);
return new_array;
}
char **fill_from_file(char **array, FILE *file)
{
char *line_buff = NULL;
size_t line_buff_size = 0;
ssize_t line_size = getline(&line_buff, &line_buff_size, file);
while (line_size >= 0) {
array = append_word_array(array, line_buff);
free(line_buff);
line_buff = NULL;
line_size = getline(&line_buff, &line_buff_size, file);
}
free(line_buff);
return array;
}
char **my_load_file_to_line_array(const char *filepath)
{
char **word_array = NULL;
FILE *file = fopen(filepath, "r");
if (!file)
return NULL;
word_array = malloc(sizeof(char *));
if (!word_array)
return NULL;
word_array[0] = NULL;
word_array = fill_from_file(word_array, file);
fclose(file);
return word_array;
}
int main(int argc, char **argv)
{
if (argc < 2)
return -1;
char **array = my_load_file_to_line_array(argv[1]);
my_free_word_array(array);
return 0;
}
我的输入测试文件:
|A B C D E F G H
-+---------------
1|. . . . . . . .
2|. . . . . . . .
3|. . . . . . . .
4|. . . . . . . .
5|. . . . . . . .
6|. . . . . . . .
7|. . . . . . . .
8|. . . . . . . .
Valgrind的报告:
❯ valgrind --leak-check=full ./navy coord.txt
==99157== Memcheck, a memory error detector
==99157== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==99157== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==99157== Command: ./navy coord.txt
==99157==
==99157==
==99157== HEAP SUMMARY:
==99157== in use at exit: 72 bytes in 5 blocks
==99157== total heap usage: 84 allocs, 79 frees, 18,512 bytes allocated
==99157==
==99157== 72 (40 direct, 32 indirect) bytes in 1 blocks are definitely lost in loss record 2 of 2
==99157== at 0x4842888: malloc (vg_replace_malloc.c:381)
==99157== by 0x10980F: append_word_array (my_load_file_to_line_array.c:18)
==99157== by 0x109914: fill_from_file (my_load_file_to_line_array.c:33)
==99157== by 0x1099F0: my_load_file_to_line_array (my_load_file_to_line_array.c:62)
==99157== by 0x1092A5: main (navy.c:17)
==99157==
==99157== LEAK SUMMARY:
==99157== definitely lost: 40 bytes in 1 blocks
==99157== indirectly lost: 32 bytes in 4 blocks
==99157== possibly lost: 0 bytes in 0 blocks
==99157== still reachable: 0 bytes in 0 blocks
==99157== suppressed: 0 bytes in 0 blocks
==99157==
==99157== For lists of detected and suppressed errors, rerun with: -s
==99157== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
1条答案
按热度按时间lx0bsm1f1#
以下是一些问题:
fill_from_file
中的line_buff = NULL;
之后将line_buff_size
重置为0
。或者更好的方法:在循环中迭代时,保持line_buff
缓冲区不断增长,并且只在循环结束后释放它。append_word_array
,以避免扫描NULL终止符。line
具有0
的长度,则测试if (line[len - 1] == '\n')
具有未定义的行为,如果文件包含嵌入的空字节,则这是可能的。malloc()
的初始调用出现分配错误,则返回NULL
,忽略fclose(file)
。realloc
是允许的,那么在append_word_array
中使用时要小心。这些问题不太可能导致报告的内存泄漏。该问题可能与您的代码(或此版本的代码)无关。您应该尝试缩短测试文件长度,并使用valgrind?发布仍能生成泄漏摘要的最小输入。
您也可以尝试此修改版本: