After mailing the list, I showed a co-worker my post, and he spent all
of 15 minutes tracking it down. MS extensions call it "Anonymous Structs":
http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
GCC has a -fms-extensions option, which does then allow this behavior.
Hurray! It appears to give me what I need for now.
-Kai Meyer
On 06/17/2011 10:33 AM, Kai Meyer wrote:
I'm basically straight out of acadamia with a 4 year CS degree, so be
gentle :)
I've been working adding a Linux port to a current Windows-only
project, and I've run into what appears to be inheritance with C
structs. I've distilled the problem down to the following code:
// Test for struct inheritance
#ifdef __cplusplus
struct base
#else
typedef struct _base
#endif
{
int b;
#ifdef __cplusplus
};
#else
} base;
#endif
#ifdef __cplusplus
struct derived : public base
{
#else
typedef struct _derived
{
base;
#endif
int d;
#ifdef __cplusplus
};
#else
} derived;
#endif
int main()
{
base b;
derived d;
b.b = 5;
d.b = b.b;
d.d = 10;
return 0;
}
It is apparent that the struct is to behave the same whether compiled
in C or C++. I admit to being a bit confused to see Polymorphism in C.
This code builds and runs in my WinDDK environment for windows, as
well as for Linux g++, but Linux gcc gives me the following error:
struct_test.c:20: warning: declaration does not declare anything
struct_test.c: In function ‘main’:
struct_test.c:33: error: ‘derived’ has no member named ‘b’
That totally makes sense. The C I know doesn't have polymorphism.
So, I need to derive a solution that will be cross-platform, and
hopefully not require any changes to existing code that uses these
structs. I'm sort of holding my breath for a gcc option like
"-magic_structs". Any help or general advice is welcome.
