This short article proposes a simple example that copies the contents of a file to another, with no error handling. Future articles will use this example as a base of comparison. This is the second from a series of articles that looks at how to deal with C APIs, resources and error handling.

Summary

I’m using the <stdio.h> functions from the previous article to copy the contents of a file src.bin to dst.bin using a 1k buffer. It opens both files, allocates the buffer, loops reading from one and writing to another until it gets to the end of the source file.

The code ignores all error handling. That makes it wrong, but otherwise an easy read.

The sample with no error handling has 28 lines of code of which the core copying takes 20 lines of code (between line 6 and 25 inclusive).

Full code

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#include <stdio.h>
#include <stdlib.h>

int main ()
{
  FILE * src = fopen("src.bin", "rb");
  FILE * dst = fopen("dst.bin", "wb");
  const size_t buffer_size = 1024;
  char * buffer = malloc(buffer_size);

  for(;;)
  {
    size_t read_count = fread(buffer, 1, buffer_size, src);
    fwrite(buffer , 1, read_count, dst);
    fputs(".", stdout);

    if (feof(src))
    {
      break;
    }
  }

  free(buffer);
  fclose(dst);
  fclose(src);

  fputs("\nSUCCESS\n", stdout);
}