Getting segmentation fault on this code

Question

I've been for a while trying to find out why i'm getting segmentation fault on this code. It's supposed to get some 11-digit numbers from a file, find out which ones start with the same 4 numbers and list them on screen.

   #include <stdio.h>

   #include <stdlib.h>

   #include <string.h>

    #define CHOP_SIZE 5

    #define INIT_CHOP 100


    typedef enum{
        OK,
        ERROR_MEMORY,
        ERROR_NULL_POINTER,
    } state_t; 

    state_t list(FILE * file,int number){
        int *v, *aux;
        size_t used_size;
        size_t alloc_size, i;
        for(used_size=0;fscanf(file,"%d",&v[used_size])==EOF;used_size++){
            if(used_size==0){
                if((v=(int*)malloc(sizeof(int)*INIT_CHOP))==NULL)return ERROR_MEMORY;
                alloc_size=1;
            }   
            if(used_size==alloc_size){
                if((aux=(int*)realloc(v,sizeof(int)*(alloc_size+CHOP_SIZE)))==NULL){
                    free(v);
                    v=NULL;
                    return ERROR_MEMORY;
                }
                alloc_size+=CHOP_SIZE;
                v=aux;
            }
        }
        for(i=0;i<used_size;i++){
            if(v[i]/10000000==number){
                printf("%d\n",v[i]);
            }
        }
        return OK;
    }

    int main(void){
        FILE *file;
        state_t state;
        file=fopen("file1","rb");
        state=list(file, 1111);
        return EXIT_SUCCESS;
    }

[Do not cast malloc in C](http://stackoverflow.com/questions/605845/do-i-cast-the-result-of-malloc) please. — gsamaras, May 16 '17 at 19:00
In order to satisfy `v[i]/10000000==1111`, `v[i]` has to be `11110000000`. Which is larger than any 32 bit number. And I doubt your `int` is more than 32 bits. — Eugene Sh., May 16 '17 at 19:01
`fscanf(file,"%d",&v[used_size])==EOF` is a strange condition. I'd expect `fscanf(file,"%d",&v[used_size])==1` — chux - Reinstate Monica, May 16 '17 at 19:09
If `"file1"` is text, open with `"r"`. If file is binary, opening with `file=fopen("file1","rb");` is OK, but `fscanf()` is a problem. Post sample `"file1"` contents. — chux - Reinstate Monica, May 16 '17 at 19:17
I suspect the "Getting segmentation fault" is that `file=fopen("file1","rb");` returns `NULL`. — chux - Reinstate Monica, May 16 '17 at 19:18

score 2 · Answer 1 · answered May 16 '17 at 19:20

2

You write to the location addressed by the uninitialized pointer v + used_size.

 for(used_size=0;fscanf(file,"%d",&v[used_size])==EOF;used_size++){

answered May 16 '17 at 19:20

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Getting segmentation fault on this code

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