What causes foo().fun() objects?

[Steven T. Hatton]

I wish I had an example so I could demonstrate. This is something I've
wanted to understand for a long time, but every time I've hit it, I've been
too busy to stop and investigate. Sometimes when I try to construct
objects of class type, I end up with weird things that look like
foo().fun(). I believe it happens like this:

Foo foo();
foo.fun();

After the call to foo.fun(); I get an error showing me I have some kind of
object called foo(). If I don't use the "()" in the constructor, that
fixes the problem. Does anybody know what I'm talking about?
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NOUN:1. Money or property bequeathed to another by will. 2. Something handed
down from an ancestor or a predecessor or from the past: a legacy of
religious freedom. ETYMOLOGY: MidE legacie, office of a deputy, from OF,
from ML legatia, from L legare, to depute, bequeath. www.bartleby.com/61/

[Markus Moll]

Hi

Steven T. Hatton wrote:

Foo foo();
foo.fun();

After the call to foo.fun(); I get an error showing me I have some kind of
object called foo(). If I don't use the "()" in the constructor, that
fixes the problem. Does anybody know what I'm talking about?

Yes, you are looking for:
http://www.parashift.com/c++-faq-lit....html#faq-10.2

Markus

[Michael K. O'Neill]

"Markus Moll" <mo**@rbg.informatik.tu-darmstadt.dewrote in message
news:45**********************@newsspool3.arcor-online.net...

Hi

Steven T. Hatton wrote:

Foo foo();
foo.fun();

After the call to foo.fun(); I get an error showing me I have some kind

of

object called foo(). If I don't use the "()" in the constructor, that
fixes the problem. Does anybody know what I'm talking about?

Yes, you are looking for:
http://www.parashift.com/c++-faq-lit....html#faq-10.2

Markus

And this, which explains it better:
http://www.parashift.com/c++-faq-lit...html#faq-10.19

[Old Wolf]

Steven T. Hatton wrote:

Sometimes when I try to construct objects of class type, I end up
with weird things. I believe it happens like this:

Foo foo();

This is not the correct syntax to construct an object of class type.
(Spending too much time on Java?)

foo.fun();

After the call to foo.fun(); I get an error showing me I have some kind of
object called foo(). If I don't use the "()" in the constructor, that
fixes the problem.

Foo foo;

is the correct syntax for constructing an object via the default
constructor.

[Steven T. Hatton]

Old Wolf wrote:

Steven T. Hatton wrote:

>Sometimes when I try to construct objects of class type, I end up
with weird things. I believe it happens like this:

Foo foo();

This is not the correct syntax to construct an object of class type.
(Spending too much time on Java?)

>foo.fun();

After the call to foo.fun(); I get an error showing me I have some kind
of
object called foo(). If I don't use the "()" in the constructor, that
fixes the problem.

Foo foo;

is the correct syntax for constructing an object via the default
constructor.

There has to be more to this, because it rarely happens to me. I'll have to
wait till it happens again to see if I can figure out why I'm doing things
differently, or why the code is acting unusually. It may simply be
flashbacks to Java. But I think there's more to it. I believe it has
happened when I do something like:

Blah * blah_ptr(new Blah());

//but

Blah * blah_ptr(new Blah);

//works.

The pointers to the FAQ were informative. They may even answer the whole
question.
--
NOUN:1. Money or property bequeathed to another by will. 2. Something handed
down from an ancestor or a predecessor or from the past: a legacy of
religious freedom. ETYMOLOGY: MidE legacie, office of a deputy, from OF,
from ML legatia, from L legare, to depute, bequeath. www.bartleby.com/61/

[John Carson]

"Steven T. Hatton" <ch********@germania.supwrote in message
news:Nt******************************@speakeasy.ne t

Old Wolf wrote:

>Steven T. Hatton wrote:

>>Sometimes when I try to construct objects of class type, I end up
with weird things. I believe it happens like this:

Foo foo();

This is not the correct syntax to construct an object of class type.
(Spending too much time on Java?)

>>foo.fun();

After the call to foo.fun(); I get an error showing me I have some
kind of
object called foo(). If I don't use the "()" in the constructor,
that fixes the problem.

Foo foo;

is the correct syntax for constructing an object via the default
constructor.

There has to be more to this, because it rarely happens to me. I'll
have to wait till it happens again to see if I can figure out why I'm
doing things differently, or why the code is acting unusually. It
may simply be flashbacks to Java. But I think there's more to it. I
believe it has happened when I do something like:

Blah * blah_ptr(new Blah());

//but

Blah * blah_ptr(new Blah);

//works.

You are allowed to have brackets when you use new, but not when you don't
use new (since the use of new enables the compiler to better distinguish
your intent).

struct S
{
S()
{cout << "S default constructor\n";}
};

struct Foo
{
Foo(S *ptr)
{ cout << "Foo\n";}
};

struct Goo
{
Goo(const S & ref)
{
cout << "Goo\n";
}
};
int main()
{
Foo foo(new S()); // works OK
Goo goo(S()); // function declaration with no effect

return 0;
}
--
John Carson