title: Issue extracting .tar file with iOS-libarchive library
body: <p>i am using iOS-libarchive library for .tar extraction on iphone. i am using the sample code given here at this link
  <a href="http://code.google.com/p/libarchive/wiki/Examples" rel="nofollow">http://code.google.com/p/libarchive/wiki/Examples</a>
   but i am facing problem in extracting .tar file.
  i am placing my .tar file in library/simulator.../Application/617C31E0/Documents folder.</p>
  
  <p>when i run application for extraction then it completes it flow successfully without giving any error code. but i could not fine that extracted folder anywhere in machine.</p>
  
  <p>here is the piece of code, i am using in my application</p>
  
  <pre><code>static int copy_data(struct archive *ar, struct archive *aw)
  {
      int r;
      const void *buff;
      size_t size;
      off_t offset;
  
      for (;;) {
          r = archive_read_data_block(ar, &amp;buff, &amp;size, &amp;offset);
          if (r == ARCHIVE_EOF)
              return (ARCHIVE_OK);
          if (r != ARCHIVE_OK)
              return (r);
          r = archive_write_data_block(aw, buff, size, offset);
          if (r != ARCHIVE_OK) {
              warn("archive_write_data_block()",
                   archive_error_string(aw));
              return (r);
          }
      }
  }
  
  static int verbose = 0;
  
  static void extract(const char *filename, int do_extract, int flags)
  {
      struct archive *a;
      struct archive *ext;
      struct archive_entry *entry;
      int r;
  
      a = archive_read_new();
      ext = archive_write_disk_new();
      archive_write_disk_set_options(ext, flags);
      /*
       * Note: archive_write_disk_set_standard_lookup() is useful
       * here, but it requires library routines that can add 500k or
       * more to a static executable.
       */
  
      archive_read_support_format_tar(a);
      /*
       * On my system, enabling other archive formats adds 20k-30k
       * each.  Enabling gzip decompression adds about 20k.
       * Enabling bzip2 is more expensive because the libbz2 library
       * isn't very well factored.
       */
  
      if (filename != NULL &amp;&amp; strcmp(filename, "-") == 0)
          filename = NULL;
      if ((r = archive_read_open_file(a, filename, 10240)))
          fail("archive_read_open_file()",
               archive_error_string(a), r);
      for (;;) {
          r = archive_read_next_header(a, &amp;entry);
          if (r == ARCHIVE_EOF)
              break;
          if (r != ARCHIVE_OK)
              fail("archive_read_next_header()",
                   archive_error_string(a), 1);
          if (verbose &amp;&amp; do_extract)
              msg("x ");
          if (verbose || !do_extract)
              msg(archive_entry_pathname(entry));
          if (do_extract) {
              r = archive_write_header(ext, entry);
              if (r != ARCHIVE_OK)
                  warn("archive_write_header()",
                       archive_error_string(ext));
              else {
                  copy_data(a, ext);
                  r = archive_write_finish_entry(ext);
                  if (r != ARCHIVE_OK)
                      fail("archive_write_finish_entry()",
                           archive_error_string(ext), 1);
              }
  
          }
          if (verbose || !do_extract)
              msg("\n");
      }
      archive_read_close(a);
      archive_read_finish(a);
      exit(0);
  }
  
  - (void)applicationDidFinishLaunching:(UIApplication *)application 
  {
      // Override point for customization after application launch
      [window makeKeyAndVisible];
  
      // Extract files from archive into named dir in the temp dir
  
      NSString*   databaseName = @"PIIS147020451170078X.tar";
      NSArray*    documentPaths =       NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
      NSString*   documentsDir = [documentPaths objectAtIndex:0];
      NSString* make7zResPath = [documentsDir stringByAppendingPathComponent:databaseName];
  
      /*  
       NSString *tmpDirname = @"Extract7z";
       NSString *make7zFilename = @"PIIS147020451170078X";//@"test.7z";
       NSString *make7zResPath = [[NSBundle mainBundle] pathForResource:make7zFilename  ofType:@"tar"];
       */
  
      extract([make7zResPath cStringUsingEncoding:NSUTF8StringEncoding],1, ARCHIVE_EXTRACT_TIME);
  
      return;  
  }
  </code></pre>
  
  <p>Please help me into this :(.</p>
  
  <p>Thanks!!</p>