Seg Fault - liste chainée doublement circulaire
Bonjour,
je demande de l'aide parce que vraiment, je ne comprends pas ce qui se passe :/
Alors voilà, je suis sous Arch Linux, et j'essaye de faire une liste chainée doublement circulaire que voici:
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| typedef struct s_elem
{
char *data;
size_t sel;
struct s_elem *prev;
struct s_elem *next;
} t_elem;
typedef struct s_box
{
t_elem *root;
size_t nbr;
size_t pos;
} t_box; |
J'execute cette fonction pour l'initialiser:
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| t_box *new_list(t_box *list)
{
if ((list = malloc(sizeof(*list))) == NULL)
{
printf( "%s\n", "[ERROR]: malloc impossible.");
exit(0);
}
list->nbr = 0;
list->pos = 0;
if ((list->root = malloc(sizeof(list->root))) == NULL)
{
printf( "%s\n", "[ERROR]: malloc impossible.");
exit(0);
}
list->root->data = NULL;
list->root->sel = 0;
list->root->prev = list->root;
list->root->next = list->root;
return (list);
} |
jusqu'ici, tout va bien. Mais dès que j'essaye de la remplir avec cette fonction, c'est une autre histoire:
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| void add_elem(t_box *list, char *val)
{
t_elem *new_elem;
t_elem *tmp;
if ((new_elem = malloc(sizeof(*new_elem))) == NULL)
{
printf( "%s\n", "[ERROR]: malloc impossible.");
exit(0);
}
tmp = list->root->next;
while (tmp != list->root)
tmp = tmp->next;
new_elem->data = val;
new_elem->sel = 0;
new_elem->prev = tmp;
new_elem->next = tmp->next;
if (tmp == list->root)
tmp->prev = new_elem;
tmp->next = new_elem;
list->root->prev = new_elem;
list->nbr = (list->nbr) + 1;
} |
Voici donc mon problème:
j'obtient un Seg Fault dans la boucle :
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| while (tmp != list->root)
tmp = tmp->next; |
de la fonction add_elem. Je n'arrive pas à comprendre pourquoi.. :/ Surtout que quand j'inverse size_t sel et struct s_elem *next dans ma structure, j'obtient cette erreur:
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| malloc.c:2365: sysmalloc: Assertion `(old_top == (((mbinptr) (((char *) &((av)->bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) >= (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 * (sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) && ((old_top)->size & 0x1) && ((unsigned long)old_end & pagemask) == 0)' failed.
Abandon (core dumped) |
Voici ce que me dit Valgrind:
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| ==7141== Memcheck, a memory error detector
==7141== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==7141== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==7141== Command: ./coucou check.c check.o functions.c functions.o includes link_list.c link_list.o main.c main.o Makefile coucou coucou.c my_select.o pos.c pos.o
==7141==
==7141== Invalid write of size 8
==7141== at 0x400CE1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141== Address 0x54410a8 is 0 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid write of size 8
==7141== at 0x400CF7: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141== Address 0x54410b0 is 8 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid write of size 8
==7141== at 0x400D09: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141== Address 0x54410b8 is 16 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid read of size 8
==7141== at 0x400DA3: add_elem (in /home/coucou)
==7141== by 0x401555: main (in /home/kinoo_m/coucou)
==7141== Address 0x54410b8 is 16 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
a==7141== Invalid read of size 8
==7141== at 0x400DBC: add_elem (in /home/coucou)
==7141== by 0x401555: main (in /home/coucou)
==7141== Address 0x54410b8 is 16 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid read of size 8
==7141== at 0x400E0D: add_elem (in /home/coucou)
==7141== by 0x401555: main (in /home/coucou)
==7141== Address 0x54410b8 is 16 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid write of size 8
==7141== at 0x400E2E: add_elem (in /home/coucou)
==7141== by 0x401555: main (in /home/coucou)
==7141== Address 0x54410b0 is 8 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid write of size 8
==7141== at 0x400E3A: add_elem (in /home/coucou)
==7141== by 0x401555: main (in /home/coucou)
==7141== Address 0x54410b8 is 16 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
==7141== Invalid write of size 8
==7141== at 0x400E49: add_elem (in /home/coucou)
==7141== by 0x401555: main (in /home/coucou/)
==7141== Address 0x54410b0 is 8 bytes after a block of size 8 alloc'd
==7141== at 0x4C27730: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7141== by 0x400CA1: new_list (in /home/coucou)
==7141== by 0x401522: main (in /home/coucou)
==7141==
acheck.cacheck.oafunctions.cafunctions.oaincludesalink_list.calink_list.oamain.camain.oaMakefileamy_selectamy_select.camy_select.oapos.c==7141==
==7141== HEAP SUMMARY:
==7141== in use at exit: 512 bytes in 17 blocks
==7141== total heap usage: 17 allocs, 0 frees, 512 bytes allocated
==7141==
==7141== LEAK SUMMARY:
==7141== definitely lost: 56 bytes in 2 blocks
==7141== indirectly lost: 456 bytes in 15 blocks
==7141== possibly lost: 0 bytes in 0 blocks
==7141== still reachable: 0 bytes in 0 blocks
==7141== suppressed: 0 bytes in 0 blocks
==7141== Rerun with --leak-check=full to see details of leaked memory
==7141==
==7141== For counts of detected and suppressed errors, rerun with: -v
==7141== ERROR SUMMARY: 93 errors from 9 contexts (suppressed: 2 from 2) |
Merci d'avance !
