C / C++ / MFC

George_George wrote:

If there is not such a built-in macro, I am not sure whether use 255? 1024 or something else is better?

George_George wrote:

Any macro used to represent computer name max length

George_George wrote:

MAX_COMPUTERNAME_LENGTH is too small and just 15 characters.

#include <Windns.h>

//
//  DNS Names limited to 255, 63 in any one label
//

#define DNS_MAX_NAME_LENGTH             (255)
#define DNS_MAX_LABEL_LENGTH            (63)

#define DNS_MAX_NAME_BUFFER_LENGTH      (256)
#define DNS_MAX_LABEL_BUFFER_LENGTH     (64)

int size;

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   NULL,
  &size
);

buffer = new char[size+1];

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   buffer,
  &size
);

George_George wrote:

You mean call this API twice?

int size = 0;

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   NULL,
  &size
);

size++;
buffer = new char[size];

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   buffer,
  &size
);

Mark Salsbery
Microsoft MVP - Visual C++