struct - double free or corruption (!prev) error with program in C -


when running program such error :

*** glibc detected *** ./prog: double free or corruption (!prev): 0x09155170 ***

the problem giving memory struct via malloc, can't what's wrong it. here code of program (in c) :

#include <stdio.h> #include <malloc.h> #include <stdlib.h> #include <string.h>  typedef struct  {       char kood[4];       int kogus;       char nimetus[80];       double hind;       int p;       int k;       int a; }ese;  void sort(int m, ese* d);  void search_kood(int m, ese* d);  void search_nimetus(int m, ese* d);  void search_kuupaev(int m, ese* d);  int menu();  int main (void) {     file *list;     list = fopen("elektroonikapood.txt", "r");     int menu_valik,m,i;     m=0;     if (list==null)       {             printf("empty or corrupted file!");             getchar();             return 0;          }       ese *esemed = (ese*) malloc(sizeof(ese));      while(!feof(list))        {                    fscanf(list, "%s", esemed[m].kood);                   fscanf(list, "%d", &esemed[m].kogus);                   fscanf(list, "%s", esemed[m].nimetus);                   fscanf(list, "%lg", &esemed[m].hind);                   fscanf(list, "%d", &esemed[m].p);                   fscanf(list, "%d", &esemed[m].k);                   fscanf(list, "%d", &esemed[m].a);                   m++;       }       while(1)    { menu_valik = menu();     if(menu_valik == 1)       sort(m, esemed);     else if (menu_valik == 2)       search_kood(m, esemed);     else if (menu_valik == 3)       search_kuupaev(m, esemed);     else if (menu_valik == 4)       search_nimetus(m, esemed);     else if (menu_valik == 0)         {           free(esemed);           fclose(list);           exit(1);        }     else       break;      }      return 0; }

there additional functions , don't think there problem them.

first... don't cast malloc in c. can hide errors.

second... malloc outside while( !feof( list ) ) loop yet allocates single instance of ese structure, you're loop implies you're loading multiple instances... means you're overwriting memory... @ point bets off.

   ese *esemed = null;     ese *lastitem = null;     while(!feof(list))     {         ese* newitem = malloc( sizeof( ese ) );          if( !esemed ) esemed = newitem;         if( lastitem ) lastitem->next = newitem;          lastitem = newitem;          fscanf(list, "%s", newitem->kood);         fscanf(list, "%d", &newitem->kogus);         fscanf(list, "%s", newitem->nimetus);         fscanf(list, "%lg", &newitem->hind);         fscanf(list, "%d", &newitem->p);         fscanf(list, "%d", &newitem->k);         fscanf(list, "%d", &newitem->a);     }

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