Thread: Callbacks?

Read up on quicksort, it's API uses a callback. Here's one link: http://www.cppreference.com/wiki/c/other/qsort

Example:

Code:

#define BUFSIZE 4096
typedef int (*do_stuff)(void *, size_t);

int readfile(const char *filename, do_stuff func)
{
  FILE *file = fopen(filename, "rb");
  void *buffer = malloc(BUFSIZE);

  if(!buffer | !file) /* Gracias a mi amigo robwhit */
  {
    if(buffer)
      free(buffer);
    if(file)
      fclose(file);
    return 0;
  }

  while(fread(buffer, BUFSIZE, 1, file))
    func(buffer, BUFSIZE);

  return 1;
}

And your callback function would just be streaming in the contents of the file.

Code:

FILE *file = fopen(filename, "rb");
void *buffer = malloc(BUFSIZE);

if(!buffer || !file)

If malloc succeeds and fopen fails, the failure would not be detected due to the short-circuiting of the || operator. To fix it, do this instead:

Code:

if (buffer && file)

Or this:

Code:

if (!buffer | !file)