structure redefinition problem

[Scoots]

I know the usually applied workaround for multiple definitions of
header files, but I have a problem on this one.

This time, I can't just ifndef the header file that defines my
structure.

So I have two classes that I've managed to dodge around this problem
for a while, but now I need the include in both classes. This wasn't
a problem until now, when I'm trying to declare an stl map with a
structure as a data type.

All I need is that structure, I don't need the rest of it. Is there a
way to extern a structure? Or do a forward declaration? I have the
include fine in the .c file, but now I want a member variable and I'm
not sure how to get it there.

Thanks,
~Scoots

 

[Victor Bazarov]

I know the usually applied workaround for multiple definitions of
header files, but I have a problem on this one.

This time, I can't just ifndef the header file that defines my
structure.

So I have two classes that I've managed to dodge around this problem
for a while, but now I need the include in both classes. This wasn't
a problem until now, when I'm trying to declare an stl map with a
structure as a data type.

All I need is that structure, I don't need the rest of it. Is there a
way to extern a structure? Or do a forward declaration? I have the
include fine in the .c file, but now I want a member variable and I'm
not sure how to get it there.

Usually, if you need a map of your type, the type has to be completely
defined, a forward declaration just won't do.

I am sorry, I can't really grasp what you're saying about managing to
dodge stuff and knowing the usually applied work-around. Perhaps you
could just post a distilled version of your code...

V

 

[Scoots]

Usually, if you need a map of your type, the type has to be completely
defined, a forward declaration just won't do.

I am sorry, I can't really grasp what you're saying about managing to
dodge stuff and knowing the usually applied work-around. Perhaps you
could just post a distilled version of your code...

V
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- Show quoted text -

Yeah, sorry, I knew at the time it was vague but I couldn't find my
definition. Finally managed to dig it up, and it is not an anonymous
struct, fortunately. In researching this, I've found references that
you can't forward declare a typedef'ed anonymous struct, and while
this is typdef'ed, it isn't anonymous.

in filea.h (inside of a dll that is included through rt.h)
typedef struct _CBREQ /* cbr */
{
LONG cbIndex;
LONG cbOffset;
LONG cbType;
} CBREQ;


programwnd.h:
#include "rt.h" //no real way to move this to programwnd.cpp, same
dependencies I need in prgengine.h

class programwnd{

}

Prgengine.h:
#include <map>

class programwnd; //forward declaration for pointer to "owner"

class Prgengine{


private:
map<string,CBREQ> variableMap
programwnd *m_masterWnd

}


in Prgengine.cpp:

#include "programwnd.h"
#include "Prgengine.h"

 

[Scoots]

Yeah, sorry, I knew at the time it was vague but I couldn't find my
definition. Finally managed to dig it up, and it is not an anonymous
struct, fortunately. In researching this, I've found references that
you can't forward declare a typedef'ed anonymous struct, and while
this is typdef'ed, it isn't anonymous.

in filea.h (inside of a dll that is included through rt.h)
typedef struct _CBREQ /* cbr */
{
LONG cbIndex;
LONG cbOffset;
LONG cbType;

} CBREQ;

programwnd.h:
#include "rt.h" //no real way to move this to programwnd.cpp, same
dependencies I need in prgengine.h

class programwnd{

}

Prgengine.h:
#include <map>

class programwnd; //forward declaration for pointer to "owner"

class Prgengine{

private:
map<string,CBREQ> variableMap
programwnd *m_masterWnd

}

in Prgengine.cpp:

#include "programwnd.h"
#include "Prgengine.h"- Hide quoted text -

- Show quoted text -

for debug purposes only I managed to get it to:

programwnd:
#include "prgengine.h"


prgengine.h:
#include "rtexec2.h"
class CProgramWnd;
class Prgengine{
private:
map<string,CBREQ> variableMap;
programwnd *m_masterWnd ;
}

prgengine.cpp:
#include "PrgStackEngine.h"
#include "programwnd.h"


which removes the need for forward declaration through nested headers
(ick), but it works for debugging and getting this going.


and I get ~20 of about these error messages: Is that a problem?
c:\program files\microsoft visual studio\vc98\include\xtree(200) :
warning C4786: '?rbegin@?$_Tree@HU?$pair@$$CBHU_CBREQ@@@std@@U_Kfn@?
$map@HU_CBREQ@@U?$less@H@std@@V?$allocator@U_CBREQ@@@3@@2@U?
$less@H@2@V?$allocator@U_CBREQ@@@2@@std@@QAE?AV?$rever
se_bidirectional_iterator@Viterator@?$_Tree@HU?$pair@$
$CBHU_CBREQ@@@std@@U_Kfn@?$map@HU_CBREQ@@U?$less@H@std@@V?
$allocator@U_CBREQ@@@3@@2@U?$less@H@2@V?$allocator@U_CBREQ@@@2@@std@@U?
$pair@$$CBHU_CBREQ@@@3@AAU43@PAU43@H@2@XZ' : identifier was trunca
ted to '255' characters in the browser information

 

[Scoots]

for debug purposes only I managed to get it to:

programwnd:
#include "prgengine.h"


prgengine.h:
#include "rtexec2.h"
class CProgramWnd;
class Prgengine{
private:
map<string,CBREQ> variableMap;
programwnd *m_masterWnd ;



}


prgengine.cpp:
#include "PrgStackEngine.h"
#include "programwnd.h"

which removes the need for forward declaration through nested headers
(ick), but it works for debugging and getting this going. So the
solution isn't urgent, for now I'll be able to continue coding, but I
would appreciate any insight you have in getting rid of this nested
header dependency.


and I get ~20 of about these error messages: but that's vs 6.0
specific.
c:\program files\microsoft visual studio\vc98\include\xtree(200) :
warning C4786: '?rbegin@?$_Tree@HU?$pair@$$CBHU_CBREQ@@@std@@U_Kfn@?
$map@HU_CBREQ@@U?$less@H@std@@V?$allocator@U_CBREQ@@@3@@2@U?
$less@H@2@V?$allocator@U_CBREQ@@@2@@std@@QAE?AV?$rever
se_bidirectional_iterator@Viterator@?$_Tree@HU?$pair@$
$CBHU_CBREQ@@@std@@U_Kfn@?$map@HU_CBREQ@@U?$less@H@std@@V?
$allocator@U_CBREQ@@@3@@2@U?$less@H@2@V?
$allocator@U_CBREQ@@@2@@std@@U?
$pair@$$CBHU_CBREQ@@@3@AAU43@PAU43@H@2@XZ' : identifier was trunca
ted to '255' characters in the browser information

 

[Victor Bazarov]

for debug purposes only I managed to get it to:

programwnd:
#include "prgengine.h"


prgengine.h:
#include "rtexec2.h"
class CProgramWnd;
class Prgengine{
private:
map<string,CBREQ> variableMap;
programwnd *m_masterWnd ;



}


prgengine.cpp:
#include "PrgStackEngine.h"
#include "programwnd.h"

which removes the need for forward declaration through nested headers
(ick), but it works for debugging and getting this going. So the
solution isn't urgent, for now I'll be able to continue coding, but I
would appreciate any insight you have in getting rid of this nested
header dependency.


and I get ~20 of about these error messages: but that's vs 6.0
specific.

Did you read them? They are not _error_ messages. They are *warnings*.
Ignore them.

c:\program files\microsoft visual studio\vc98\include\xtree(200) :
warning C4786: '?rbegin@?$_Tree@HU?$pair@$$CBHU_CBREQ@@@std@@U_Kfn@?
$map@HU_CBREQ@@U?$less@H@std@@V?$allocator@U_CBREQ@@@3@@2@U?
$less@H@2@V?$allocator@U_CBREQ@@@2@@std@@QAE?AV?$rever
se_bidirectional_iterator@Viterator@?$_Tree@HU?$pair@$
$CBHU_CBREQ@@@std@@U_Kfn@?$map@HU_CBREQ@@U?$less@H@std@@V?
$allocator@U_CBREQ@@@3@@2@U?$less@H@2@V?
$allocator@U_CBREQ@@@2@@std@@U?
$pair@$$CBHU_CBREQ@@@3@AAU43@PAU43@H@2@XZ' : identifier was trunca
ted to '255' characters in the browser information

V

 

[=?ISO-8859-1?Q?Erik_Wikstr=F6m?=]

Yeah, sorry, I knew at the time it was vague but I couldn't find my
definition. Finally managed to dig it up, and it is not an anonymous
struct, fortunately. In researching this, I've found references that
you can't forward declare a typedef'ed anonymous struct, and while
this is typdef'ed, it isn't anonymous.

in filea.h (inside of a dll that is included through rt.h)
typedef struct _CBREQ /* cbr */
{
LONG cbIndex;
LONG cbOffset;
LONG cbType;
} CBREQ;

Not related to your problem but unless you have to maintain
compatibility with C you don't need the typedef, just

struct CBREQ {
// ...
};

will do. And when I'm at it, all-caps identifiers are generally reserved
for macros.