[haiku-bugs] [Haiku] #6373: Bluetooth address macros are broken
- From: "zooey" <trac@xxxxxxxxxxxx>
- Date: Fri, 23 Jul 2010 19:49:25 -0000
#6373: Bluetooth address macros are broken
--------------------------------------------+-------------------------------
Reporter: zooey | Owner: oruizdorantes
Type: bug | Status: new
Priority: normal | Milestone: R1
Component: Network & Internet/Bluetooth | Version: R1/alpha2
Keywords: | Blocked By:
Has a Patch: 0 | Platform: All
Blocking: |
--------------------------------------------+-------------------------------
The bluetooth.h header defines these bdaddr_t macros:
{{{
#define BDADDR_NULL (&(bdaddr_t) {{0, 0, 0, 0, 0, 0}})
#define BDADDR_LOCAL (&(bdaddr_t) {{0, 0, 0, 0xff, 0xff,
0xff}})
#define BDADDR_BROADCAST (&(bdaddr_t) {{0xff, 0xff, 0xff, 0xff,
0xff, 0xff}})
}}}
However, the concept of getting an address of a compound literal is pretty
much broken, as compound literals are neither part of the C++ standard
(though gcc supports them) and their lifetime is not well-controlled
inside of a macro.
As an example:
{{{
struct foo {
bdaddr_t peer;
};
void bar()
{
foo myfoo;
if (...)
myfoo.peer = BDADDR_LOCAL;
else
myfoo.peer = BDADDR_NULL;
// try doing something with myfoo, but the actuall bdaddr_t object
will
// be dead here already, so the data at the address myfoo.peer may
have
// been overwritten
}
}}}
Instead, I suggest doing something along the lines of:
{{{
extern const bdaddr_t __BDADDR_NULL;
extern const bdaddr_t __BDADDR_LOCAL;
extern const bdaddr_t __BDADDR_BROADCAST;
#define BDADDR_NULL (&__BDADDR_NULL)
#define BDADDR_LOCAL (&__BDADDR_LOCAL)
#define BDADDR_BROADCAST (&__BDADDR_BROADCAST)
}}}
and then define these constants somewhere in an implementation file that
gets linked by all users of those macros.
--
Ticket URL: <http://dev.haiku-os.org/ticket/6373>
Haiku <http://dev.haiku-os.org>
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