Question

I am new to c++/parsing, I convert the xsd file into an auto generated cpp and header file. When I try to access the element (member functions) of the xml file (xmlfilename) I am getting the error “Primary-expression missing before’->’ token”.

My code:

#include "IMACSMsgHeaderType.h"
#include<iostream>
#include<string>
#include <memory>

#include <xercesc/util/PlatformUtils.hpp>
#include <xercesc/util/XMLString.hpp>
#include <xercesc/dom/DOM.hpp>
#include <xercesc/util/OutOfMemoryException.hpp>
#include <xercesc/parsers/XercesDOMParser.hpp>

using namespace std;
using namespace SelfTest;

int main()
  {
 try{
   ::std::auto_ptr< ::SelfTest::MH > xsd (::SelfTest::MH_ ("bala.xml",::xml_schema::flags::dont_validate));
}
catch(const xml_schema::exception& e)
{
    cerr<<e.what()<<endl;        
}
cout<<xsd->n();
return 1;
}

complier output:

vmware@LSS01:~/Desktop/private> make
g++ -c test_classParsing.cpp 
test_classParsing.cpp: In function ‘int main()’:
test_classParsing.cpp:26: error: expected primary-expression before ‘->’ token
make: *** [.o] Error 1

Can anyone explain what is the Primary expression error? and how can I solve this?

More details:

  #include <memory>    
  #include <algorithm> 
  #include <xsd/cxx/tree/exceptions.hxx>
  #include <xsd/cxx/tree/elements.hxx>
  #include <xsd/cxx/tree/containers.hxx>
  #include <xsd/cxx/tree/list.hxx>
  #include <xsd/cxx/xml/dom/parsing-header.hxx>
  #include "IMACSTypes.h"

 #include<iosfwd>
 #include<xercesc/dom/DOMDocument.hpp>
 #include<xercesc/dom/DOMErrorHandler.hpp>
 #include<xercesc/framework/XMLFormatter.hpp>
 #include<xsd/cxx/xml/dom/auto-ptr.hxx>

 namespace SelfTest
 {
    class MH: public ::xml_schema::type
   {
     public:
   // hdrSize
    // 
    typedef ::xml_schema::unsigned_int hdrSize_type;
    typedef ::xsd::cxx::tree::optional< hdrSize_type > hdrSize_optional;
    typedef ::xsd::cxx::tree::traits< hdrSize_type, char > hdrSize_traits;

const hdrSize_optional&
hdrSize () const;

hdrSize_optional&
hdrSize ();

void
hdrSize (const hdrSize_type& x);

void
hdrSize (const hdrSize_optional& x);

// a
// 
typedef ::SelfTest::MessageIDType a_type;
typedef ::xsd::cxx::tree::traits< a_type, char > a_traits;

const a_type&
a () const;

a_type&
a ();

void
a (const a_type& x);

void
a (::std::auto_ptr< a_type > p);

// b
// 
typedef ::SelfTest::DestinationType b_type;
typedef ::xsd::cxx::tree::traits< b_type, char > b_traits;

const b_type&
b () const;

b_type&
b ();

void
b (const b_type& x);

void
b (::std::auto_ptr< b_type > p);

// n
// 
typedef ::xml_schema::string n_type;
typedef ::xsd::cxx::tree::traits< n_type, char > n_traits;

const n_type&
n () const;

n_type&
n ();

void
n (const n_type& x);

void
n (::std::auto_ptr< n_type > p);
// Constructors.

MH (const a_type&,
    const b_type&,
    const n_type&,
   );

MH (const ::xercesc::DOMElement& e,
    ::xml_schema::flags f = 0,
    ::xml_schema::container* c = 0);

MH (const MH& x,
    ::xml_schema::flags f = 0,
    ::xml_schema::container* c = 0);

virtual MH*
_clone (::xml_schema::flags f = 0,
        ::xml_schema::container* c = 0) const;

virtual 
~MH ();

// Implementation.
//
protected:
void
parse (::xsd::cxx::xml::dom::parser< char >&,
       ::xml_schema::flags);

protected:
hdrSize_optional hdrSize_;
::xsd::cxx::tree::one< a_type > a_;
::xsd::cxx::tree::one< b_type > b_;
::xsd::cxx::tree::one< n_type > n_;
 };

  ::std::auto_ptr< ::SelfTest::MH >
   MH_ (const ::std::string& uri, ::xml_schema::flags f = 0,const ::xml_schema::properties& p = ::xml_schema::properties ());

}

i have no idea where i am wrong pls some one guide me..Thanks in advance

Answer 1

Your xsd goes out of scope when you leave the try block. Try moving the cout into try like this:

int main()
{
    try
    {
      std::auto_ptr< SelfTest::MH > 
      xsd( SelfTest::MH_("bala.xml", xml_schema::flags::dont_validate) );
      cout << xsd->n();
    }
    catch(const xml_schema::exception& e)
    {
        cerr << e.what() << endl;        
    }

    return 0;
}

The operations of auto_ptr are guaranteed not to throw. So alternatively you can do this as well if you want to limit the scope of your try block:

int main()
{
    std::auto_ptr< SelfTest::MH > xsd;
    try
    {
      xsd.reset( SelfTest::MH_("bala.xml", xml_schema::flags::dont_validate) );
    }
    catch(const xml_schema::exception& e)
    {
        cerr << e.what() << endl;        
    }
    if( xsd.get() )
      cout << xsd->n();

    return 0;
}

Note, your main should return 0 if there’s no error.