Each security group has a unique identifier with associated information, such as a name and a domain. This information is usually stored in an operating system database, such as /etc/group or the Network Information Service (NIS) in UNIX, or the Security Account Manager (SAM) in Windows NT. The os_group class provides a portable method for accessing and manipulating this information.

Example <ospace/security/examples/group1.cpp>


  #include <iostream>
#include <ospace/security.h>

void
main()
  {
  os_security_toolkit initialize;

  // Construct to reference group "cavemen".
  os_group group1( string( "cavemen" ) );

  // Construct group2 to reference group with GID 1.
  os_group group2( 1 );

  cout << "group1 = " << group1 << end1;
  cout << "group2 = " << group2 << end1;

  cout << group1 << " == " << group2 << " = ";
  cout << (group1 == group2) << endl;
  cout << group1 << " == " << group1 << " = ";
  cout << (group1 == group1) << endl;
  }

group1 = os_group( cavemen, 21 )
group2 = os_group( daemon, 1 )
os_group( cavemen, 21 ) == os_group( daemon, 1 ) = 0
os_group( cavemen, 21 ) == os_group( cavemen, 21 ) = 1

On UNIX systems, you can list the users that belong to a group by using users() . In addition, you can use the static function groups() to obtain a list of all groups in the system, as shown in the following example.

Example <ospace/security/examples/group2.cpp>


  #include <iostream>
#include <ospace/security.h>

void
main()
  {
  os_security_toolkit initialize;

  os_group group( "cavemen" );
  vector< uid_t > users = group.users();
  cout << group << " has the following users: " << endl;
  vector< uid_t >::iterator i;
  for ( i = users.begin(); i != users.end(); i++ )
    cout << "  " << os_user( *i ) << endl;
  cout << endl;

  vector< gid_t > groups = os_group::groups();
  cout << "List of all the groups in the group database:" << endl;
  vector< gid_t >::iterator j;
  for ( j = groups.begin(); j != groups.end(); j++ )
    cout << "  " << os_group( *j ) << endl;
  }

os_group( cavemen, 21 ) has the following users:
  os_user( ned, 101 )
  os_user( fred, 100 )
  ...
  os_user( sysrel, 136 )

List of all groups in the group database:
  os_group( wheel, 0 )
  os_group( cavemen, 21 )
  ...
  os_group( daemon, 1 )

The next example, executed on a Windows NT workstation, returns the domain information for a particular group.

Example <ospace/security/examples/group4.cpp>


  #include <iostream>
#include <ospace/security.h>

void
main()
  {
  os_security_toolkit initialize;

  os_group group( "Technical" );
  cout
    << "Group \'" << group.name()
    << "\' belongs to the domain \'"<< group.domain()
    << "\'." << endl;
  }

Group 'Technical' belongs to the domain 'OBJSPACE'.

Refer to the dir4.cpp example in File<ToolKit> for a more complex example that uses both os_group and os_user .