ISO C++ forbids declaration of 'Rectangle' with no type

[Florian Haag]

Hello,
I'm trying to compile a programme which compiles fine under Linux; I'm
trying it with MinGW G++ 3.4.2:


Component.h:

#ifndef COMPONENT_H_
#define COMPONENT_H_

#include "../basics/Rectangle.h"

class Component {
private:
Rectangle *bounds;
// Unique identifier
long id;

// more declarations

};

#endif


Rectangle.h (relative path is as included above):

#ifndef RECTANGLE_H_
#define RECTANGLE_H_

#include "Point.h"

class Rectangle
{
// some declarations
};

#endif


Point.h (same directory as Rectangle.h)

#ifndef POINT_H_
#define POINT_H_

class Point {
// some declarations
};

#endif


Now, in Windows, I always get the following compilation errors (where
line 25 in Component.h matches the line "Rectangle *bounds;" shown
above):

In file included from visdgetsbase.h:13,
from main.cpp:14:
widgets/Component.h:25: error: ISO C++ forbids declaration of
`Rectangle' with n
o type
widgets/Component.h:25: error: expected `;' before '*' token
widgets/Component.h:41: error: ISO C++ forbids declaration of
`Rectangle' with n
o type
widgets/Component.h:41: error: expected `;' before '*' token
widgets/Component.h:43: error: variable or field `setBounds' declared
void
widgets/Component.h:43: error: expected `;' before '(' token

So, why isn't Rectangle recognized as a type?

I tried removing the relative path in #include, but that only results
in an additional error message saying that the file Rectangle.h wasn't
found at all. I also made sure I don't have any other file called
Rectangle.h on my entire hard disk, so quite obviously, with the
relative paths given in the #include directive, the correct file
should've been found, then why isn't the type Rectangle?

Thanks in advance,
Florian

 

[=?iso-8859-1?q?Erik_Wikstr=F6m?=]

Hello,
I'm trying to compile a programme which compiles fine under Linux; I'm
trying it with MinGW G++ 3.4.2:

Component.h:

#ifndef COMPONENT_H_
#define COMPONENT_H_

#include "../basics/Rectangle.h"

class Component {
private:
Rectangle *bounds;
// Unique identifier
long id;

// more declarations

};
#endif

In file included from visdgetsbase.h:13,
from main.cpp:14:
widgets/Component.h:25: error: ISO C++ forbids declaration of
`Rectangle' with no type

Seems to me like the problem might be on line 25 in Component.h (or a
bit above), but the part from Component.h you pasted does not contain
the 25th line so I can't help you. Make sure that the last statement
above line 25 has a ; at the end.

 

[Florian Haag]

Seems to me like the problem might be on line 25 in Component.h (or a
bit above), but the part from Component.h you pasted does not contain
the 25th line so I can't help you. Make sure that the last statement
above line 25 has a ; at the end.

Hi,
sorry if I explained this in a confusing way, actually, the line

Rectangle *bounds;

_is_ line 25, already shown in my code in the original posting (I
removed some comments when copying the code here).

Regards, thanks in advance,
Florian

 

[Kai-Uwe Bux]

Hi,
sorry if I explained this in a confusing way, actually, the line

Rectangle *bounds;

_is_ line 25, already shown in my code in the original posting (I
removed some comments when copying the code here).

Well, in removing that code, you probably removed the error. Post those
lines. (This is covered in the FAQ:

www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.8


Best

Kai-Uwe Bux

 

[Florian Haag]

Well, in removing that code, you probably removed the error. Post
those lines. (This is covered in the FAQ:

www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.8

Sorry, this sent me to the right direction; there was a naming conflict
with a Rectangle-function from wingdi.h, which of course only occurred
in Windows.
I'm sorry for not having followed those rules, I still am not used that
in C++, there can be such an influence accross several files, unlike in
some other languages.

Regards,
Florian

 

[Bo Persson]

Sorry, this sent me to the right direction; there was a naming
conflict with a Rectangle-function from wingdi.h, which of course
only occurred in Windows.
I'm sorry for not having followed those rules, I still am not used
that in C++, there can be such an influence accross several files,
unlike in some other languages.

So C++ provides namespaces to isolate different components into their own
space.


Bo Persson

 

[Noah Roberts]

with a Rectangle-function from wingdi.h, which of course only occurred
in Windows.
I'm sorry for not having followed those rules, I still am not used that
in C++, there can be such an influence accross several files, unlike in
some other languages.

Other languages usually solve this "problem" with namespaces. It is
rare that a language allows the same symbol to be used to mean
different things.

 

[Florian Haag]

Other languages usually solve this "problem" with namespaces. It is
rare that a language allows the same symbol to be used to mean
different things.

Right, well - e.g. in Delphi, if you include another source file A, by
default, you just include the declarations from that very source file
A, not those of other source files B and C referenced by A.

Regards,
Florian