From: hchen3@uwo.ca
Sent: Tuesday, February 12, 2002 3:54 PM
To: Info-VAX@Mvb.Saic.Com
Subject: Re: Question about Group ID

Hi ALL:

  Thanks for the help on this particular topic. I learn a lot from all
you guys (yeah, and the manual too -> a great read). I post the source 
code below and if there is any mistakes, please point out. Thanks again
for all the great insight.

Sammy



int main(int argc, char* argv[])
{

  if (argc != 2) 
  {
    cout << "invalid parameter count" << endl;
    return 1;
  }
	
  unsigned int context = 0;
  unsigned short int length = 0;;
  unsigned int resid = 0;
  unsigned int attibute = 0;
  char name[1024];

  struct dsc$descriptor_s grp;

  grp.dsc$w_length = 1024;
  grp.dsc$b_dtype = DSC$K_DTYPE_T;
  grp.dsc$b_class = DSC$K_CLASS_S;
  grp.dsc$a_pointer = name;

  int status;
  struct stat statBuf;
  int stat_rc;

  double shift = pow(2.0, 16.0);

  if ((stat_rc = stat((char *) "fun.cpp", &statBuf)) != 0)
  {
    cerr << "stat failed"  << endl;
    return -1;
  }

  if (!S_ISREG(statBuf.st_mode))  // only regular file allowed
  {
    cerr << "file is not regular" << endl;
    return -1;
  }
	
  unsigned int id = statBuf.st_gid * ((int) shift);

  // look up group name 
  status = SYS$IDTOASC(id, &length, &grp, &resid, &attibute, &context);

  switch(status)
  {
    case SS$_ACCVIO:
      cout << "access violation"  << endl;
      break;

    case SS$_INSFMEM:
      cout << "insufficient dynamic memory" << endl;
      break;

    case SS$_IVCHAN:
      cout << "invalid content in context" << endl;
      break;

    case SS$_IVIDENT:
      cout << "invalid format for identifier" << endl;
      break;

    case SS$_NOIOCHAN:
      cout << "No more rights database context streams are available." << endl;
      break;

    case SS$_NORIGHTSDB:
      cout << "The rights database does not exist" << endl;
      break;

    case SS$_NOSUCHID:
      cout << "The specified identifier name does not exist in the rights 
	      database, or the entire rights database has been searched if 
              the ID is --1." << endl;
      break;

    default:
		
      if(strcasecmp(argv[1], name) == 0)
      {
        cout << "Group name matched" << endl;
      }
			
      else cout << "Group name mismatched" << endl;
		
      break;

  }
  return 0;
}