winforms - Can't access global variables -

in globaldata.h defining typedef struct globaldata. in main cpp program, i'm including globaldata.h, declaring
globaldata globaldata;

after declaration, include createnetdialog.h , gui.h. why can reference globaldata in gui.h not createnetdialog.h? both include files should pasted .cpp file during precompile, globaldata should visible in both right?

i have globaldata structure defined here:
globaldata.h

typedef struct {     string netfilename;     datafilereader *datafilereader; } globaldata; 

in c++ code, have:
gui.cpp

#include <cstdlib> #include <iostream> #include <fstream> #include <string> #include "datafilereader.h" #include "globaldata.h"  globaldata globaldata;  #include "createnetdialog.h" #include "gui.h"   using namespace system; using namespace system::windows::forms; using namespace std;  [stathread] void main(array<string^>^ args) {     application::enablevisualstyles();     application::setcompatibletextrenderingdefault(false);      carnac::gui formmain;     application::run(%formmain); } 

createnetdialog.h (in createnetdialog constructor)

#pragma once   namespace carnac {      using namespace system;     using namespace system::componentmodel;     using namespace system::collections;     using namespace system::windows::forms;     using namespace system::data;     using namespace system::drawing;      /// <summary>     /// summary createnetdialog     /// </summary>     public ref class createnetdialog : public system::windows::forms::form     {     public:         createnetdialog(void)         {             initializecomponent();              // left of '.size' must have class/struct/union             // left of '.datafilereader' must have class/struct/union             // 'globaldata':undeclared identifier despite being declared right before             // file included in .cpp file             (unsigned int i=0; i<globaldata.datafilereader->_headeritems.size(); i++)             {                            //             }         }      protected:         /// <summary>         /// clean resources being used.         /// </summary>         ~createnetdialog()         {             if (components)             {                 delete components;             }         }     protected:       protected:       private: system::windows::forms::button^  buttoncreate;     private: system::windows::forms::button^  buttoncreatecancel;         private:         system::componentmodel::container ^components;  #pragma region windows form designer generated code         void initializecomponent(void)         {             this->buttoncreate = (gcnew system::windows::forms::button());             this->buttoncreatecancel = (gcnew system::windows::forms::button());             this->suspendlayout();             //              // buttoncreate             //              this->buttoncreate->anchor = static_cast<system::windows::forms::anchorstyles>((system::windows::forms::anchorstyles::bottom | system::windows::forms::anchorstyles::left));             this->buttoncreate->location = system::drawing::point(16, 288);             this->buttoncreate->name = l"buttoncreate";             this->buttoncreate->size = system::drawing::size(75, 23);             this->buttoncreate->tabindex = 7;             this->buttoncreate->text = l"create";             this->buttoncreate->usevisualstylebackcolor = true;             //              // buttoncreatecancel             //              this->buttoncreatecancel->anchor = static_cast<system::windows::forms::anchorstyles>((system::windows::forms::anchorstyles::bottom | system::windows::forms::anchorstyles::right));             this->buttoncreatecancel->location = system::drawing::point(404, 288);             this->buttoncreatecancel->name = l"buttoncreatecancel";             this->buttoncreatecancel->size = system::drawing::size(75, 23);             this->buttoncreatecancel->tabindex = 8;             this->buttoncreatecancel->text = l"cancel";             this->buttoncreatecancel->usevisualstylebackcolor = true;             this->buttoncreatecancel->click += gcnew system::eventhandler(this, &createnetdialog::buttoncreatecancel_click);             //              // createnetdialog             //              this->autoscaledimensions = system::drawing::sizef(6, 13);             this->autoscalemode = system::windows::forms::autoscalemode::font;             this->clientsize = system::drawing::size(491, 323);             this->controls->add(this->buttoncreatecancel);             this->controls->add(this->buttoncreate);             this->name = l"createdialog";             this->text = l"createdialog";             this->resumelayout(false);             this->performlayout();          } #pragma endregion     private: system::void buttoncreatecancel_click(system::object^  sender, system::eventargs^  e)     {                  this->close();     } }; } 

gui.h (at end)

#pragma once  #include <msclr\marshal_cppstd.h>  namespace carnac {      using namespace system;     using namespace system::componentmodel;     using namespace system::collections;     using namespace system::windows::forms;     using namespace system::data;     using namespace system::drawing;      /// <summary>     /// summary gui     /// </summary>     public ref class gui : public system::windows::forms::form     {         public:         gui(void)         {             initializecomponent();             //             //todo: add constructor code here             //         }          protected:         /// <summary>         /// clean resources being used.         /// </summary>         ~gui()         {             if (components)             {                 delete components;             }         }         protected:           private: int _datacolumnselected;         private: system::windows::forms::button^  buttonload;          private:         /// <summary>         /// required designer variable.         /// </summary>         system::componentmodel::container ^components;  #pragma region windows form designer generated code         /// <summary>         /// required method designer support - not modify         /// contents of method code editor.         /// </summary>         void initializecomponent(void)         {             this->buttonload = (gcnew system::windows::forms::button());             this->suspendlayout();             //              // buttonload             //              this->buttonload->anchor = static_cast<system::windows::forms::anchorstyles>((system::windows::forms::anchorstyles::bottom | system::windows::forms::anchorstyles::left));             this->buttonload->text = l"load data";             this->buttonload->usevisualstylebackcolor = true;             this->buttonload->click += gcnew system::eventhandler(this, &gui::buttonload_click);             this->buttonload->location = system::drawing::point(67, 66);             this->buttonload->name = l"buttonload";             this->buttonload->size = system::drawing::size(75, 23);             this->buttonload->tabindex = 0;             this->buttonload->usevisualstylebackcolor = true;             //              // gui             //              this->autoscaledimensions = system::drawing::sizef(6, 13);             this->autoscalemode = system::windows::forms::autoscalemode::font;             this->backcolor = system::drawing::systemcolors::appworkspace;             this->clientsize = system::drawing::size(234, 171);             this->controls->add(this->buttonload);             this->name = l"gui";             this->text = l"carnac";             this->resumelayout(false);          } #pragma endregion         static std::string tostandardstring(system::string^ string)         {             using system::runtime::interopservices::marshal;             system::intptr pointer = marshal::stringtohglobalansi(string);             char* charpointer = reinterpret_cast<char*>(pointer.topointer());             std::string returnstring(charpointer, string->length);             marshal::freehglobal(pointer);             return returnstring;         }          private: system::void buttonpredictrun_click(system::object^  sender, system::eventargs^  e)         {         }         private: system::void buttontestload_click(system::object^  sender, system::eventargs^  e)         {         }         private: system::void buttonload_click(system::object^  sender, system::eventargs^  e)         {            openfiledialog^ openfiledialog1 = gcnew openfiledialog;             openfiledialog1->filter = "data files|*.dat";             if (openfiledialog1->showdialog() == system::windows::forms::dialogresult::ok)            {                ifstream infile;                 string^ strfilename = openfiledialog1->initialdirectory + openfiledialog1->filename;                 // works                // why can use globaldata here not in createnetdialog.h?                globaldata.datafilereader = new datafilereader(tostandardstring(strfilename));            }         }     }; } 

thanks help

yes, globaldata visible in both gui.h , createnetdialog.h, when compiled gui.cpp. in globaldata.h have defined type, not global variable of type. when compiled other cpp file, gui.h , createnetdialog.h can't see declaration of global variable in gui.cpp.

here's want do: declare both type, , extern global variable in globaldata.h. include globaldata.h every file want use in, don't rely on other files have included before 1 want use in. in just one cpp file (currently gui.cpp), declare actual global variable.

// globaldata.h #include "datafilereader.h" typedef struct {     string netfilename;     datafilereader *datafilereader; } globaldata;  extern globaldata globaldata; 

.

// every file use globaldata #include "globaldata.h" 

.

// gui.cpp #include "globaldata.h"  globaldata globaldata;