macros/2483: not even the macro debugging example from the documentation works

[christian@jaeger.mine.nu]

>Number:         2483
>Category:       macros
>Synopsis:       not even the macro debugging example from the documentation works
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jul 25 00:18:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     christian@jaeger.mine.nu
>Release:        6.8-debian
>Organization:
>Environment:
Debian testing, gcc (Debian 4.3.1-2) 4.3.1
>Description:
I tried compiling a big program with -gdwarf-2 -g3 in the hope that I could expand / use shown macros, which didn't work. I then tried the examples in the info Macros page ("9 C Preprocessor Macros"), and did exactly (I think) as shown, and could in fact expand the ADD macro, but not the Q macro. It looks like macros from header files are somehow ignored?
>How-To-Repeat:
$ gcc -gdwarf-2 -g3 sample.c -o sample
$ gdb sample
..
(gdb) list main
3	
4	     #define M 42
5	     #define ADD(x) (M + x)
6	
7	     main ()
8	     {
9	     #define N 28
10	       printf ("Hello, world!\n");
11	     #undef N
12	       printf ("We're so creative.\n");
(gdb) info macro ADD
Defined at /tmp/chris/sample.c:5
#define ADD(x) (M + x)
(gdb) info macro Q
The symbol `Q' has no definition as a C/C++ preprocessor macro
at /tmp/chris/sample.c:13
(gdb) break main
Breakpoint 1 at 0x4004d4: file sample.c, line 10.
(gdb) run
Starting program: /tmp/chris/sample 

Breakpoint 1, main () at sample.c:10
10	       printf ("Hello, world!\n");
(gdb) info macro N
Defined at /tmp/chris/sample.c:9
#define N 28
(gdb) macro expand N Q M
expands to: 28 Q 42
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: