Dependencies, Namespace, and Headers - c++

Question

I believe have dug myself into a hole. While breaking up my single file, couple thousand line chunk of code into multiple files I appear to have grossly screwed up the structure of the program.
I'm new to C++ and its header files and namespace management so I've been learning as I go.
I guess I don't fully understand how #include, using, and namespaces interrelate and what transfers over to other files, etc.
Reading through MSDN documentation I can see bits and pieces of my problem but the solution eludes me.
As of now I have four .cpp files and headers:
1) A Main File
2) A GameData .cpp and its header that is contained in the namespace pData
3) A GameSettings .cpp and its header that is contained in the namespace pSettings
4) A GeneralScreens .cpp and its header that is contained in the namespace pScreens
Upon compile the debugger spews over 100 of error like:
>c:\program files (x86)\microsoft visual studio 10.0\vc\include\utility(454): error C2447: '{' : missing function header (old-style formal list?)
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\utility(463): error C2039: 'pair' : is not a member of 'std'
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\utility(463): error C2955: 'pScreens::std::pair' : use of class template requires template argument list
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\utility(173) : see declaration of 'pScreens::std::pair'
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(33): error C2873: 'wcsrtombs' : symbol cannot be used in a using-declaration
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(41): error C2039: 'wctob' : is not a member of '`global namespace''
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(41): error C2873: 'wctob' : symbol cannot be used in a using-declaration
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(42): error C2039: 'wmemchr' : is not a member of '`global namespace''
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(42): error C2873: 'wmemchr' : symbol cannot be used in a using-declaration
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(42): error C2039: 'wmemcmp' : is not a member of '`global namespace''
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(42): error C2873: 'wmemcmp' : symbol cannot be used in a using-declaration
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(42): error C2039: 'wmemcpy' : is not a member of '`global namespace''
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(42): error C2873: 'wmemcpy' : symbol cannot be used in a using-declaration
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\cwchar(43): error C2039: 'wmemmove' : is not a member of '`global namespace''
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\new(93): error C2039: 'nothrow_t' : is not a member of 'std'
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\new(93): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\new(93): error C2143: syntax error : missing ',' before '&'
1>c:\program files (x86)\microsoft visual studio 10.0\vc\include\new(99): error C2039: 'new_handler' : is not a member of 'std'
Are these errors indicative of something?
I'm assuming something is wrong with the way I'm referencing the std library though I have no idea how to pinpoint the error because all the errors are in library files.

Answer 1

Most likely you're missing a semicolon on the end if a class or struct definition in a header file. The compiler then treats every identifier it sees as an instance of that class instead of what you're expecting. Then the compiler complains because it has no idea what to do with the stray {}s it sees.
Check the header that's #included just before <utility> in your implementation file; that header is most likely where the fault lies.
Side note: To avoid this problem, always #include standard headers before your own headers in a .CPP file. For example, instead of
// MyGameThing.cpp
#include "MyGameThing.hpp"
#include <utility>
#include <string>
// code
do
// MyGameThing.cpp
#include <utility>
#include <string>
#include "MyGameThing.hpp"
// code
That way you won't get compile errors like this buried in the standard headers.

Answer 2

The first compiler error is going to be your best clue:
c:\program files (x86)\microsoft visual studio 10.0\vc\include\utility(454): error C2447: '{' : missing function header (old-style formal list?)
I'm guessing that what's happening here is you may have a class or struct declaration with no ending semicolon. So you have something like this:
struct Foo
{
} // <--- no semicolon here will generate funky errors
But overall, pay close & special attention to the first compiler error.
As #Billy mentions in the comments below, the rules for struct and class are the same. In either case, you need the semicolon. Also, old-school C code will often typedef structs like this:
typedef struct tag_Foo
{
} Foo; // <-- still need the semicolon
Here, you still need the semicolon.

Answer 3

If using Visual C++, open the first cpp file and press CTRL+F7, this will compile only the cpp file, check the first error and try to correct this. When fixed go to the next cpp file if the error persists.

Answer 4

Billy's attempt is a decent one, but the usual response to a missing ';' is for the compiler to say so. A missing '}' on the other hand can seriously confuse standard headers included afterward because all their content is within the scope of either the namespace or class that should have been closed. Also, ';' missing is more immediately detectable while a missing '}' isn't necessarily an error so the compiler just pisses a fit at the first thing that doesn't make sense in that scope.
Furthermore, at line 454 in utility for the 2010 compiler is the opening brace for a specialization of tuple_size for std::pair. Post preprocessor that definition would look like so:
template < ... >
struct tuple_size< ::std::pair<_Ty1, _Ty2> >
If you have forgotten a '}' closing a namespace then that's not where pair<> exists anymore. Instead, since it's declared like so:
namespace std { template < ... > struct pair ... }
Whatever scope wasn't closed is now where std is being declared and struct tuple_size< ::std::pair<...> > doesn't make any sense to the parser. Since it's not a valid name it tends to pretend it's not even there and then '{' at the global scope without anything of sense before it is pretty f'n confusing.
BTW, an often unspoken benefit of making minimal examples that cause the problem is that you end up FINDING the problem trying to make it happen.