Linked List in C not working Valgrind Error -

the program supposed read words of file linked list. got linked list working i'm faced error. i'm getting segmentation fault when using large file.

it working smaller lists (3-10 words) not larger ones.

-----code----- #include <stdio.h> #include <stdlib.h> #include <string.h>  typedef struct node //struct linked list {     char* word;     struct node* next; } node;    int main (void) {             char* dictfile = "large";      file* dict = fopen(dictfile, "r");      if (dict == null)         return 1;      node* head = null;             char* oneword = malloc(sizeof(node));  //to store word fgets()      while ((fscanf (dict, "%s", oneword)) > 0)     {                                                 node* temp = (node*)malloc(sizeof(node));          char* tempword = (char*)malloc(sizeof(node)); //gives me new pointer store string (as pointed out antione)          strcpy(tempword, oneword);          temp->word = tempword;          printf("%s\n", temp->word);     //prints value (just debug)          temp->next = head;                     head = temp;                  }      node* temp = (node*)malloc(sizeof(node));     temp = head;      while(temp != null)    //loop print linked list     {                    printf("traverse %s\n", temp->word);    //prefix 'ing traverse know linked list         temp = temp->next;     }      free(head);     free(temp);     fclose(dict);      printf("success!!\n");        }     

the result follows:

./tempeol .............lots of words below acceptor acceptor's tempeol: malloc.c:2372: 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. aborted (core dumped) 

valgrind shows invalid writes @ few places.

one strcpy(). have account additional null character resolve don't know how.

    -----valgrind error----- jharvard@appliance (~/dropbox/pset5): valgrind ./tempeol ==4709== memcheck, memory error detector ==4709== copyright (c) 2002-2013, , gnu gpl'd, julian seward et al. ==4709== using valgrind-3.10.0.svn , libvex; rerun -h copyright info ==4709== command: ./tempeol ==4709==  aaa aaas aachen aalborg ==4709== invalid write of size 1 ==4709==    @ 0x40db401: _io_vfscanf (vfscanf.c:1180) ==4709==    0x40e21f6: __isoc99_fscanf (isoc99_fscanf.c:34) ==4709==    0x8048681: main (tempeol.c:25) ==4709==  address 0x423b1c0 0 bytes after block of size 8 alloc'd ==4709==    @ 0x402a17c: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so) ==4709==    0x8048662: main (tempeol.c:23) ==4709==  ==4709== invalid read of size 1 ==4709==    @ 0x402d4f1: strcpy (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so) ==4709==    0x80486d5: main (tempeol.c:31) ==4709==  address 0x423b1c0 0 bytes after block of size 8 alloc'd ==4709==    @ 0x402a17c: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so) ==4709==    0x8048662: main (tempeol.c:23) ==4709==  aalesund 

help needed!!

also funny thing: if change char* tempword = (char*)malloc(sizeof(node)); char* tempword = (char*)malloc(sizeof(node)*512); end getting full linked list segmentation fault @ end.

i feel solution lies in line of code. ideas??

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thanks @drc , @lurker, i've got working. valgrind shows no errors. no segmentation faults. :)

here's final working code needs it:

================working code:: solution============ #include <stdio.h> #include <stdlib.h> #include <string.h>  typedef struct node //struct linked list {     char* word;     struct node* next; } node;    int main (void) {             char* dictfile = "small";      file* dict = fopen(dictfile, "r");      if (dict == null)         return 1;      node* head = null;             char oneword[28];  //to store word fscanf()      while ((fscanf (dict, "%s", oneword)) > 0)     {                                                 node* temp = (node*)malloc(sizeof(node));          char* tempword = (char*)malloc(strlen(oneword)+1); //gives me new pointer store string (as pointed out antione)          strcpy(tempword, oneword);          temp->word = tempword;          //printf("%s\n", temp->word);     //prints value (just debug)          temp->next = head;                     head = temp;                  }      node* temp = head;      while(temp != null)    //loop print linked list     {                    printf("%s\n", temp->word);    //prefix 'ing traverse know linked list         temp = temp->next;     }      printf("\n");      free(head);     //free(temp);   //no need (drc)     fclose(dict);      printf("success!!\n");        }     

i can sleep now...

you have correct line of code first problem. malloc memory hold string based on sizeof(node). instead, should of length strlen(oneword)+1. right now, long word write beyond buffer.

char* tempword = (char*)malloc(strlen(oneword)+1); 

in lines:

...}  node* temp = (node*)malloc(sizeof(node)); temp = head;  while(temp != null)  ... 

you assign temp malloc'd storage , set temp head - leaking storage (minor).

very minor item - call free(temp) @ end waste temp null.