libc.so and getlogin

Hi

I have some code wich retrieve UNIX initial login name of user:

procedure getlogin external "libc.so" cdecl:

DEFINE RETURN PARAMETER login_char AS MEMPTR NO-UNDO.               

end procedure.                                                                                                                           

def var login_char as memptr.                                                                                                         

def var s as char.                                                                                                                                                                                                 

run getlogin(output login_char).

assign s = get-string(login_char,1) no-error.

disp s.

But s is aways empty.

I need help.

OpenEdge 10.1B03 64Bit

SunSparc Solaris 5.10 64Bit