I failed to open a named "Event Object" created by another process (also my
program)
, and it returned error #5 (Access is denied.). Why is that?

I tried to supply SECURITY_ATTRIBUTES with CreateEvent() like:

SECURITY_ATTRIBUTES s_att;
s_att.nLength = sizeof(SECURITY_ATTRIBUTES);
s_att.lpSecurityDescriptor = 0;
s_att.bInheritHandle = 1;
wait_obj = CreateEvent( &s_att, 0, 0, name );

But still failed.

Can somebody help me?

--------------
Kenji Chan

Kenji Chan wrote:

If the other process is a service then it must supply a
SECURITY_ATTRIBUTES when it creates the event, and it must be a valid
SECURITY_ATTRIBUTES, not just a NULL descriptor. I also suspect that
you can't get away with allocating these SECURITY_ATTRIBUTES on the
stack: Make them exist for the lifetime of the app(s).

--
Scott McPhillips [VC++ MVP]

Yes, my another program is a service run as "Local System"
If two programs run as the same account, everything is fine
I'm really not sure how to open a named event object that created by a
"System" process, can somebody give me some hints.

Anyway I tried something like:

SID sid;
SECURITY_DESCRIPTOR sd;
SECURITY_ATTRIBUTES s_att;
SID_NAME_USE sid_name;
void somefunc( char *name ){

DWORD dwsid = sizeof(SID);
char domainname[1024];
DWORD dwname = sizeof( domainname );
InitializeSecurityDescriptor( &sd, SECURITY_DESCRIPTOR_REVISION );

if ( !LookupAccountName( 0, "System", &sid, &dwsid, domainname, &dwname,
&sid_name ) ) printf("LookupAccountName error\n");
if ( !SetSecurityDescriptorOwner( &sd, &sid, 1 ) )
printf("SetSecurityDescriptorOwner error#%u\n", GetLastError());

printf("%s %d\n", domainname, sid_name);
s_att.nLength = sizeof(SECURITY_ATTRIBUTES);
s_att.lpSecurityDescriptor = &sd;
s_att.bInheritHandle = 1;

wait_obj = CreateEvent( &s_att, 0, 0, name );
.....
}

But still failed with #5 (Access is denied)

Why?