Question

The well known method for this is to declare int globalVar = 0 and then -where to use it- extern int globalVar; but that didn’t work with me for objects from user defined class!

This is an example of what I did:

file1.cpp:

 #include "file2.h"  
class list { ....};  
 list * x ;       
//do something with x` 

file2.cpp:

class list;  
 extern list * x;  
//do something with x

and this is the error I get:

error C2027: use of undefined type 'list'

if I remove class list

error C2143: syntax error : missing ';' before '*' // in `extern list *x;`  
error C4430: missing type specifier - int assumed. Note: C++ does not support 
             default-int

thanks for answers , now it’s like this :

#ifndef _ERRLIST_H_
#define _ERRLIST_H_
#include <queue>
#include <string>

struct errorStruct{
            int errLineNum;
            int errColNum ;
            char * errMessage;
    };
queue <errorStruct> errQueue; //error points here
class ErrList
{

public:
void pushError(int line,int col,char * message);
void popError();    
void printErrors();
int getSize();

};
#endif

but I get this error :

error C2143: syntax error : missing ';' before '<'

Answer 1

error C2143: syntax error : missing ‘;’ before ‘<‘

It’s “std::queue<errorStruct>”, not “queue<errorStruct>”.