Help with a #define

Wynd · 04-22-2007, 01:02 PM

I was looking through the C source for a program and came across this. Can someone tell me what it does?

Code:

#define SET_INT(x){ .i = (x) }

Is this some kind of shorthand?

dmail · 04-22-2007, 01:36 PM

Id say it is an evil macro,yet I do not understand what the dot operator is doing there. Can you find an instance in the source where it is used?

Wynd · 04-22-2007, 02:39 PM

It is code for an AIM client if that matters or helps at all. Here is one instance where it is used, in setting up the preference variables.

Code:

struct global_pref global_pref[] = {
	{	"ACTIVITY_TYPES",
		OPT_INT,
		0,
		opt_set_int,
		NULL,
		SET_INT(DEFAULT_ACTIVITY_TYPES)
	}
// Many others here...
};

dmail · 04-22-2007, 03:05 PM

That is truly EVIL, a global array has the same name as a struct?
Anyway its just setting the i field in the structure to the value supplied so:

Code:

struct foo
{
int a;
int b;
int c;
int i;
};

struct foo foo_array[] = {.a = 0, 1, 0, .i = 4};

So it more than likely that global_pref has a structure which has an i field.

Wynd · 04-22-2007, 03:30 PM

OK, thanks a lot