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17/10/2007, 23h15

Richard Heathfield <rjh@see.sig.invalid> writes:
> Fred Phillips said:
>> Title says ["What's the use of anonymous structs?"]
>
> As far as I can discern, C doesn't provide such a feature. So the answer is
> "none, as far as C is concerned". If your implementation provides such a
> feature as an extension, consult its documentation to find out why.

Maybe. It depends on what the OP is really asking about.

You can declare something like this:

struct {
int x;
int y;
} obj;

The struct object "obj" is clearly not anonymous (its name is "obj"),
but the struct type has no name.

The advantage of this, I suppose, is that if you're only going to have
one object of the type, a name for the type would be superfluous. It
might be a decent way to provide a logical grouping for a set of
objects (almost like a C++ namespace, but far more restrictive).

But if C required all struct types to have a tag ("struct foo { ... }"),
it wouldn't have caused any real problems. In the few cases where the
tag name is irrelevant, you could just make up something arbitrary.

> As a rule, "What's the use of..." questions are pretty pointless. If you
> can't think of a use for something, don't use it.

It depends. If I'm learning a new language, and I run across a
feature for which I can't think of a use, learning how it's actually
used can be very instructive.

--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

17/10/2007, 23h15	#6
Keith Thompson Messages: n/a Hébergeur:	Re: What's the use of anonymous structs? Richard Heathfield <rjh@see.sig.invalid> writes: > Fred Phillips said: >> Title says ["What's the use of anonymous structs?"] > > As far as I can discern, C doesn't provide such a feature. So the answer is > "none, as far as C is concerned". If your implementation provides such a > feature as an extension, consult its documentation to find out why. Maybe. It depends on what the OP is really asking about. You can declare something like this: struct { int x; int y; } obj; The struct object "obj" is clearly not anonymous (its name is "obj"), but the struct type has no name. The advantage of this, I suppose, is that if you're only going to have one object of the type, a name for the type would be superfluous. It might be a decent way to provide a logical grouping for a set of objects (almost like a C++ namespace, but far more restrictive). But if C required all struct types to have a tag ("struct foo { ... }"), it wouldn't have caused any real problems. In the few cases where the tag name is irrelevant, you could just make up something arbitrary. > As a rule, "What's the use of..." questions are pretty pointless. If you > can't think of a use for something, don't use it. It depends. If I'm learning a new language, and I run across a feature for which I can't think of a use, learning how it's actually used can be very instructive. -- Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst> San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst> "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister"