以下是两个函数，其中第一个函数根据计数值尝试分配并随后为指针数组重新分配内存。
第二个函数尝试将最后一个字符串连接到指针数组中的第一个字符串。
程序接受字符串数和要匹配的模式作为命令行参数，并且只有在输入字符串中找到匹配模式时才调用第一个函数。
20 char **allocate_array_of_ptrs(char **str_array, /* pointer to the array of pointers */
21 char *str, /* pointer to the input string */
22 int count) /* count of matched strings */
23 {
24 char **temp = NULL; /* temporary pointer to realloc memory */
25
26 /* realloc based on count value */
27 temp = (char **)realloc(str_array, count * sizeof(char *));
28
29 int str_len = strlen(str);
30
31 /* if realloc is successful */
32 if (NULL != temp)
33 {
34 str_array = temp;
35
36 /* alloc memory for the string to be stored */
37 temp[count - 1] = (char *)calloc((str_len + 1), sizeof(char));
38 strcpy(temp[count - 1], str);
39 }
40
41 return str_array;
42 }
43
44 char **dmm_str_cat(char **str_array, /* pointer to the array of pointers */
45 int count) /* count of matched strings */
46 {
47 int i; /* iterator */
48 int total_str_len = 0; /* total length when all strings put together */
49 int str_len_of_first; /* string length of first string in the array */
50
51 if (count > 1)
52 {
53 str_len_of_first = strlen(str_array[0]);
54
55 for (i = 0; i < count; i++)
56 {
57 total_str_len += strlen(str_array[i]);
58 }
59 total_str_len += 1;
60
61 /* realloc memory to accomodate all matched strings onto first string */
62 str_array[0] = (char *)realloc(str_array[0], total_str_len * sizeof(char));
63
64 /* clearing the new allocated bytes */
65 for (i = (str_len_of_first + 1); i < total_str_len; i++)
66 {
67 str_array[0][i] = '\0';
68 }
69
70 /* concatenate from the last string onwards onto first string */
71 for (i = count - 1; i > 0; i--)
72 {
73 strcat(str_array[0], str_array[i]);
74 }
75 }
76
77 return str_array;
78 }
问题是当代码在valgrind下运行时，它会在3个字符串中报告以下消息，2个字符串与模式“el”不匹配。其他组合也报告了类似的错误。
Enter string 1 : matter
Enter string 2 : matter
Enter string 3 : jello
Count of strings having matching pattern 'el' : 1
The matching strings are :
jello
==6244== Invalid read of size 8
==6244== at 0x400A74: main (dmm_main.c:86)
==6244== Address 0x4C33038 is 0 bytes after a block of size 8 alloc'd
==6244== at 0x4A05809: malloc (vg_replace_malloc.c:149)
==6244== by 0x4A05883: realloc (vg_replace_malloc.c:306)
==6244== by 0x400AE9: allocate_array_of_ptrs (dmm_functions.c:27)
==6244== by 0x4009B6: main (dmm_main.c:64)
==6244==
==6244== Invalid write of size 8
==6244== at 0x400A89: main (dmm_main.c:87)
==6244== Address 0x4C33038 is 0 bytes after a block of size 8 alloc'd
==6244== at 0x4A05809: malloc (vg_replace_malloc.c:149)
==6244== by 0x4A05883: realloc (vg_replace_malloc.c:306)
==6244== by 0x400AE9: allocate_array_of_ptrs (dmm_functions.c:27)
==6244== by 0x4009B6: main (dmm_main.c:64)
The concatenated string is : jello==6244==
==6244== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 4 from 1)
==6244== malloc/free: in use at exit: 0 bytes in 0 blocks.
==6244== malloc/free: 2 allocs, 2 frees, 14 bytes allocated.
==6244== For counts of detected errors, rerun with: -v
==6244== All heap blocks were freed -- no leaks are possible.
但是当有两个匹配模式的字符串而一个不匹配时，valgrind报告没有错误/泄漏。当所有字符串都与模式匹配时，就会报告肯定丢失。
答案 0 :(得分：1)
考虑到您的阅读无效，然后写入无效，我认为传递给str_array的{{1}}未正确初始化 -
实际上，消息allocate_array_of_ptrs让我觉得你超越了数组的大小但是如果没有main.c代码，我就无法100％确定。