Question

i am currently rewriting a log parsing script from bash into C, and i was just wondering if i could get some advice regarding how i can set the array called buffer to expand dynamically instead of being limited to 1024, I think i would use malloc, but im not too sure how to properly implement it for this specific application, any help is greatly appreciated, thanks!

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define _GNU_SOURCE
void main(int argc, char *argv[], char *envp[])
{
  FILE *fd;
  char *name;
  name = getenv("MCEXEC_PLAYERNAME");
  char *filename;
  filename = malloc(sizeof "/home/minecraft/freedonia/playerdata/deathlog-.txt" - 1 +    strlen(name) + 1);
  if (!filename) exit(EXIT_FAILURE);
  sprintf(filename,"/home/minecraft/freedonia/playerdata/deathlog-%s.txt",name);
  char buff[1024];
  if ((fd = fopen(filename, "r")) != NULL)
  {
    fseek(fd, 0, SEEK_SET);

    while(!feof(fd))
    {
      memset(buff, 0x00, 1024);
      fscanf(fd, "%[^\n]\n", buff);
    }
    printf("%s\n", buff);
  }
  else
  printf( "fail" );
}

Answer 1

Use malloc to allocate the array dynamically.

If needed, realloc it to alter its size.

EDIT:

Instead of: char buff[1024];

use:

char *buff;
buff = malloc(1024); //This will allocate 1024 chars

You can use another variable like: char tmp[256]; to read from file and store it into buff. As you put tmp into buff, keep note of the size of chars in buff. If necessary, make a call to realloc:

len = sizeof(buff);
buff = realloc(buff, len+256); //This will increase the buff size by 256