writing multiple file gives segmentation fault, signle file doesn't

Question

I wrote a function to write the linked list data to a file, when I write main() and the WriteData() in a single file, then it works just fine. But when I write the WriteData() in a different file and include it in main file using a header file, it gives me segmentation fault. Here's my code

abcd.h:

#ifndef _ABCD_H_
#define _ABCD_H_
struct node{
  char word[50];
  char sort[50];
  struct node *next;
}
void WriteData(struct node *head);
void read_data(struct node **head, FILE *fp);
#endif

main.c:

#include"abcd.h"
int main(int argc, char *argv[]) //file is given as command line argument
{
  FILE *fp = fopen(argv[1], "r");
  struct node *head = NULL;
  read_data(&head, fp); //loads the contents of the file to the list
  WriteData(head);
}

writeData.c:

#include"abcd.h"
void WriteData(struct node *head)
{
  FILE *fp = fopen("dictionary.txt", "w");
  if(fp == NULL){
    printf("Error opening file..\n"); 
    return;
  } 
  while(head != NULL){
    fprintf(fp, "\n%s:", head->word);
    fprintf(fp, "%s", head->sort);
    head = head->next;
  } 
  fclose(fp);
  printf("Data saved successfully..\n");
}

readData.c:

#include "abcd.h"
void read_data(struct node **head, FILE *fp)
{
  if(fp == NULL){
    printf("Error opening file..\n");
    return;
  }
  struct node temp;
  temp.next = NULL;
  struct node *hp, *curr;
  hp = *head;
  while(!feof(fp)){
    fscanf(fp, " %[^:]", temp.word);
    fseek(fp, 1, SEEK_CUR);
    fscanf(fp, " %[^\n]", temp.sort);
    struct node *temp2 = (struct node*)malloc(sizeof(struct node));
    if(temp2 == NULL){
      printf("Couldn't make new node by malloc:");
      return;
    }
    *temp2 = temp;
    if(hp == NULL){
      curr = hp = temp2;
    } 
    else
      curr = curr->next = temp2;
  }
  fclose(fp);
  *head = hp;
  printf("Data loaded successfully..\n");
}

Error:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7a5cc80 in _IO_vfprintf_internal (s=0x604830, 
     format=<optimized out>, ap=ap@entry=0x7fffffffd928) at vfprintf.c:1632
1632    vfprintf.c: No such file or directory.

Answer 1

I fixed some typo in your code and this is my version:

main.c

#include "hd.h"

int main(int argc, char *argv[]) //file is given as command line argument
{
  FILE *fp = fopen(argv[1], "r");
  struct node *head = NULL;

  //read_data(&head, fp); //loads the contents of the file to the list
 WriteData(head);
}

hd.h

#ifndef _hd_h_
#define _hd_h_
struct node{
  char word[50];
  char sort[50];
  struct node *next;
};

#include <stdio.h>
extern void WriteData(struct node *head);

#endif

write.c

#include "hd.h" 

void WriteData(struct node *head)
{
  FILE *fp = fopen("dictionary.txt", "w");
  if(fp == NULL){
    printf("Error opening file..\n"); 
    return;
  } 
  while(head != NULL){
    fprintf(fp, "\n%s:", head->word);
    fprintf(fp, "%s", head->sort);
    head = head->next;
  } 
  fclose(fp);
  printf("Data saved successfully..\n");
}

Compile with GCC:

gcc -Wall main.c write.c -o prog

You should consider we must compile two .c file, and link them together to make an executable object code (binary file) under the name of main.

Then we can invoke loader program in Unix-like machine to load and execute the program main with typing this command in terminal then hitting the Enter key.

Run

./main

[Edit- ToDo]

Thanks for Basile Starynkevitch for precious comments and show some faults in my post.

1. Separate Compilation and Linkage process.
2. Automate them with make file.
3. Some extra improvement, explanation, documents.
4. Use different linker program.
5. Make some improvement on Codes.