How to read the standard input into string variable until EOF in C?

Question

I am getting \"Bus Error\" trying to read stdin into a char* variable. I just want to read whole stuff coming over stdin and put it fi

Answer 1

The problem here is that you are referencing a pointer variable that no memory allocated via malloc, hence the results would be undefined, and not alone that, by using strcat on a undefined pointer that could be pointing to anything, you ended up with a bus error!

This would be the fixed code required....

char* content = malloc (100 * sizeof(char));
char c;
if (content != NULL){
   content[0] = '\0'; // Thanks David!
   while ((c = getchar()) != EOF)
   {
       if (strlen(content) < 100){
           strcat(content, c);
           content[strlen(content)-1] = '\0';
       }
   }
}
/* When done with the variable */
free(content);

The code highlights the programmer's responsibility to manage the memory - for every malloc there's a free if not, you have a memory leak!

Edit: Thanks to David Gelhar for his point-out at my glitch! I have fixed up the code above to reflect the fixes...of course in a real-life situation, perhaps the fixed value of 100 could be changed to perhaps a #define to make it easy to expand the buffer by doubling over the amount of memory via realloc and trim it to size...