GetUserNameEx function (Windows)

GetUserNameEx function

GetUserNameEx function

Applies to: desktop apps only

Retrieves the name of the user or other security principal associated with the calling thread. You can specify the format of the returned name.

If the thread is impersonating a client, GetUserNameEx returns the name of the client.

Syntax

BOOLEAN WINAPI GetUserNameEx(
  __in     EXTENDED_NAME_FORMAT NameFormat,
  __out    LPTSTR lpNameBuffer,
  __inout  PULONG lpnSize
);

Parameters

NameFormat [in]

The format of the name. This parameter is a value from the EXTENDED_NAME_FORMAT enumeration type. It cannot be NameUnknown. If the user account is not in a domain, only NameSamCompatible is supported.

lpNameBuffer [out]

A pointer to a buffer that receives the name in the specified format. The buffer must include space for the terminating null character.

lpnSize [in, out]

On input, this variable specifies the size of the lpNameBuffer buffer, in TCHARs. If the function is successful, the variable receives the number of TCHARs copied to the buffer, not including the terminating null character.

If lpNameBuffer is too small, the function fails and GetLastError returns ERROR_MORE_DATA. This parameter receives the required buffer size, in Unicode characters (whether or not Unicode is being used), including the terminating null character.

Return value

If the function succeeds, the return value is a nonzero value.

If the function fails, the return value is zero. To get extended error information, call GetLastError. Possible values include the following.

Return code	Description
ERROR_MORE_DATA	The lpNameBuffer buffer is too small. The lpnSize parameter contains the number of bytes required to receive the name.
ERROR_NO_SUCH_DOMAIN	The domain controller is not available to perform the lookup
ERROR_NONE_MAPPED	The user name is not available in the specified format.

Requirements

Minimum supported client	Windows 2000 Professional
Minimum supported server	Windows 2000 Server
Header	Secext.h (include Security.h)
Library	Secur32.lib
DLL	Secur32.dll
Unicode and ANSI names	GetUserNameExW (Unicode) and GetUserNameExA (ANSI)

the only thing that worked for me to get rid of the "define one of these" errors was to
//#define SECURITY_KERNEL
#define SECURITY_WIN32
//#define SECURITY_MAC
#include <security.h>
#include <secext.h>
GetUserNameEx()

(note the order)

in an earlier post, I had incorrectly stated that I had thought that only SECURITY_KERNEL worked.

if you forget to include security.h, then only SECURITY_KERNEL works, but if I include security.h before secext.h I was able to #define either SECURITY_WIN32 or SECURITY_KERNEL. (I did not test SECURITY_MAC because I don't have a mac - what does SECURITY_MAC mean anyway? what does SECURITY_KERNEL mean? what are these and what does it do to my code?)

I also incorrectly stated that you only had to include the 2 headers to get this working (this is what the manual currently says).
After some testing I discovered this also to be false. you absolutely MUST #define ONE of the SECURITY_ codes listed above at the top of your program or it will compile with an error stating that you must #define one of the 3 SECURITY_ codes above.

Syntax

Parameters

Return value

Requirements

See also