Question

我正在使用哈希数组制作项目。我正在放一张我在网上找到的图片，向大家展示我正在尝试做的事情。 image

所以我已经在main中像这样初始化了左侧的大数组：

cellule_t * array[HASH_MAX] = {NULL};

然后我进行了所有插入操作以创建链接列表。我现在想做的是释放所有分配来创建所有内存的内存。因此，就像我不在大型数组上使用malloc一样，我只需要释放链表，就可以使用此功能：

但是我从Valgrind那里得到了一些错误，并且这些块无法释放。我将使用的所有功能（包括主要功能）都变得更加清晰。

typedef struct cell{

   char *mot;
   char *traduction;
   struct cell *suivant;

}cellule_t;

int main()
{
int indice;
cellule_t *cel;
FILE*file = NULL;
char buffer[100] = "hello bye glass sorry";    
cellule_t *tabMajeur[HASH_MAX] = {0};
file = fopen("fichier.txt","r");
remplissage_hachage(tabMajeur,file);    (c:157)
affichageTraduction(tabMajeur,buffer);
libererMemorie(tabMajeur);  (c:159)

}

void remplissage_hachage (cellule_t **tabMajeur,FILE *fichier)
{
char  string1[20];
unsigned int indice = 0;
cellule_t *copy;
int boolean = 0;
char *string2, *string3 = NULL;
cellule_t *c =NULL;


while(fgets(string1,100,fichier) != NULL)
{
    string2 = strtok(string1,";");
    string3 = strtok(NULL,";"); 
    string3[strlen(string3)-1] = '\0';
    printf("string2 %s\n",string2);
    printf("string3 %s\n",string3);
    indice = hash_string(string2);
    boolean = 0;
    indice = recherche(tabMajeur,string2,&boolean,&c);

    if(boolean != 1) 
    {
        copy = tabMajeur[indice];
        tabMajeur[indice] = creationCellule(string2,string3); (c: 64)
        tabMajeur[indice]->suivant = copy;    
    }
}


}



cellule_t* creationCellule(char * mot, char *traduction)
{

  cellule_t *nouveau = (cellule_t *) malloc(sizeof(cellule_t)); (c:24)

  if(nouveau != NULL)
  {
    nouveau -> mot = strdup(mot);
    nouveau -> traduction = strdup(traduction);
    nouveau -> suivant = NULL;
  }

  return nouveau;

}



void libererMemorie(cellule_t **tabMajeur)
{

int i = 0;
cellule_t * cour;
cellule_t * copy;
for(i = 0 ; i < HASH_MAX; i++)
{
    cour = tabMajeur[i];
    while(cour != NULL)
    {
        copy = cour;
        free(copy); (c:137)
        cour = cour->suivant; (c:138)
    }

}
}

valgrind错误为： enter image description here

valgrind错误的文本是：

==2550== Memcheck, a memory error detector
==2550== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==2550== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==2550== Command: ./tp4
==2550== 
string2 hello
string3 bonjour
string2 bye
string3 au revoir
string2 sorry
string3 pardon
string2 glass
string3 verre
La traduction est bonjour au revoir verre pardon 
==2550== Invalid read of size 8
==2550==    at 0x108E55: libererMemorie (tp4.c:138)
==2550==    by 0x108F85: main (tp4.c:159)
==2550==  Address 0x522ea40 is 16 bytes inside a block of size 24 free'd
==2550==    at 0x4C30D3B: free (in 
   /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
 ==2550==    by 0x108E50: libererMemorie (tp4.c:137)
==2550==    by 0x108F85: main (tp4.c:159)
 ==2550==  Block was alloc'd at
==2550==    at 0x4C2FB0F: malloc (in 
/usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
 ==2550==    by 0x108A5D: creationCellule (tp4.c:24) 
 ==2550==    by 0x108BD8: remplissage_hachage (tp4.c:64)
==2550==    by 0x108F60: main (tp4.c:157)
==2550== 
==2550== 
==2550== HEAP SUMMARY:
==2550==     in use at exit: 605 bytes in 9 blocks
==2550==   total heap usage: 15 allocs, 6 frees, 5,821 bytes allocated
==2550== 
==2550== LEAK SUMMARY:
==2550==    definitely lost: 53 bytes in 8 blocks
==2550==    indirectly lost: 0 bytes in 0 blocks
==2550==      possibly lost: 0 bytes in 0 blocks
==2550==    still reachable: 552 bytes in 1 blocks
==2550==         suppressed: 0 bytes in 0 blocks
==2550== Rerun with --leak-check=full to see details of leaked memory
==2550== 
==2550== For counts of detected and suppressed errors, rerun with: -v
==2550== ERROR SUMMARY: 4 errors from 1 contexts (suppressed: 0 from 0)

能帮我找出问题所在吗？

Answer 1

“无效读取”错误可能源于以下事实：在哈希表中每个存储桶都有一个单链接列表时，您试图释放列表节点，然后在访问后访问下一个节点的指针。已经释放了当前节点。

所以基本上在这里：

D      getRecording  573287126069013  2019-06-07 15:03:09.609  Function execution started
       getRecording  573287126069013  2019-06-07 15:03:09.789  Analyzing gs://my-bucket/audio_trimed.wav
D      getRecording  573287126069013  2019-06-07 15:03:10.979  Function execution took 1372 ms, finished with status: 'error'
E      getRecording  573291408785013  2019-06-07 15:03:11.990  Error: Requested entity was not found.
                                                                   at Http2CallStream.call.on (/srv/functions/node_modules/@grpc/grpc-js/build/src/client.js:101:45)
                                                                   at Http2CallStream.emit (events.js:194:15)
                                                                   at Http2CallStream.EventEmitter.emit (domain.js:459:23)
                                                                   at Http2CallStream.endCall (/srv/functions/node_modules/@grpc/grpc-js/build/src/call-stream.js:63:18)
                                                                   at handlingTrailers (/srv/functions/node_modules/@grpc/grpc-js/build/src/call-stream.js:152:18)
                                                                   at process._tickCallback (internal/process/next_tick.js:68:7)

您正在创建未定义的行为，因为要释放节点，然后尝试通过copy = cour; free(copy); cour = cour->suivant;指针访问释放的内存，以获取链表中的下一个指针。为cour分配copy的值只会复制指针值本身。然后，您释放了cour和copy所指向的内存，然后尝试在已释放的块中访问该内存。 Valgrind绝对不会那样。

您可以简单地将订单更改为以下内容：

cour

现在，在内存块仍然是有效分配的内存块的同时，将当前节点中的内存复制出指向下一个节点的指针。

在链接列表中使用free（）的Valgrind错误

1 个答案: