Hi, Ian and Mike,
Thanks for the information.
Now I understand the following code is "the value of the member b of a
compound literal which is initialized by a designated initializer". Is
it correct ?
( ( union { int a; int b; }) { .a =7 }).b
Regards,
Mike
----- Original Message -----
From: "Ian Lance Taylor" <iant@xxxxxxxxxx>
To: "Michael Gong" <mwgong@xxxxxxxxxxxxxx>
Cc: "Michael Gong" <mwgong@xxxxxxxxxxxxxx>; <gcc-help@xxxxxxxxxxx>
Sent: Monday, December 11, 2006 3:09 PM
Subject: Re: what's this syntax?
"Michael Gong" <mwgong@xxxxxxxxxxxxxx> writes:
My question is how to interperate the code, since I don't understand
its syntax.
If it is a C99 code, what's the C99 feature for it ?
I'm sorry, I don't understand this question. What kind of answer are
you looking for?
>> void foo() {
>> if(
>> ( __extension__
>> (
>> (
>> (
>> union {
>> int a;
>> int b;
>> }
>> ) { .a =7 }
This is a constructor expression. The type is the anonymous union.
The value is the initializer expression, which in this case sets field
'a' to '7'.
>> ) .b
This is a reference to field 'b' of the newly constructed union. It
should be zero or garbage, I can't remember which.
>> )
>> ) == 7 ) {
>> printf("abc\n");
>> }else {
>> printf("def\n");
>> }
>> }
Ian
