c++ - I assign a pointer and it nulls itself out -

so have constructor object, on creation sets few values , places @ end of linked list.

the problem i'm having when assigns address of new object head or tail of list, assigns, leaves constructor , reason head , tail both reset 0.

object object1("oddjob", 2, 2, 9); 

calls constructor

object::object(string label, float x, float y, float z) {   x_ = x;   y_ = y;   z_ = z;   if(label == "")   {     label = "object";   }   label_ = label;   if(headobject == 0)   {     headobject = this;     tailobject = this;   }   else   {     tailobject->next = this;     tailobject = this;   }   next = 0; } 

edit: headobject , tailobject globals declared in .h file. declared as:

static object * headobject; static object * tailobject; 

the use of static on global object causes have internal linkage. means each translation unit includes header have own version of headobject , tailobject.

instead, should declare them extern in header file:

extern object * headobject; extern object * tailobject; 

then in single translation unit (typically .cpp corresponding .h), should give definitions as:

object * headobject; object * tailobject; 

you can't define them in header file, otherwise you'll break 1 definition rule when include header in multiple files.