sqlite3 c++ forward declaration of struct sqlite3 leads to invalid pointer error on delete in destructor -

using eclipse cdt on linux. here code , warnings during compile:

 #ifndef databaseconnection_hpp_ #define databaseconnection_hpp_  #include <sqlite3.h> #include <string>  using namespace std;  class databaseconnection { private:     sqlite3 *_database; public:     // constructors     databaseconnection(const string &databaseuri, char mode='w');      // destructor     ~databaseconnection(); };  #endif /* databaseconnection_hpp_ */ 

the source

/*  * databaseconnection.cpp  *  *  created on: mar 31, 2015  *      author: michael wilson (mnw380@gmail.com)  */  #include <databaseconnection.hpp> #include <exception.hpp> #include <sqlite3.h> #include <stdlib.h> #include <sstream> #include <formattedstring.hpp> #include <fileutils.hpp>  using namespace std;  databaseconnection::databaseconnection(const string &databaseuri, char mode) {     if (mode != 'w' && mode != 'r')         throw exception("exception databaseconnection::databaseconnection. mode must \'r\' or \'w\' read/write connection mode");      int flags = (mode == 'w') ? sqlite_open_readwrite : sqlite_open_readonly;      // enables opening databases using uri     flags |= sqlite_open_uri;      // verify database uri formed correctly     if ( !formattedstring::isformatted(databaseuri, "file:/.*") && !formattedstring::isformatted(databaseuri, "http:/.*") ) {         // if not formed using standard uri syntax, assume file path , verify exists         if ( !fileutils::exists(databaseuri) )             throw exception("exception databaseconnection::databaseconnection. file not exist: " + databaseuri);     }       // returns non-zero on open error     if ( sqlite3_open_v2(databaseuri.c_str(), &_database, flags, null) ) {         ostringstream ss;         ss << "exception databaseconnection::databaseconnection. error opening database " << databaseuri;         throw exception(ss.str());     } }  databaseconnection::~databaseconnection() {     sqlite3_close(_database);     delete _database; } 

and warnings during compile

g++ -i/opt/ros/indigo/include -i"/home/user/workspace/project/include" -o0 -g3 -wall -c -fmessage-length=0 -std=gnu++11 -mmd -mp -mf"src/databaseconnection.d" -mt"src/databaseconnection.d" -o "src/databaseconnection.o" "../src/databaseconnection.cpp" ../src/databaseconnection.cpp: in destructor ‘databaseconnection::~databaseconnection()’: ../src/databaseconnection.cpp:48:9: warning: possible problem detected in invocation of delete operator: [enabled default]   delete _database;          ^ ../src/databaseconnection.cpp:48:9: warning: invalid use of incomplete type ‘struct sqlite3’ [enabled default] in file included /home/user/workspace/project/include/databaseconnection.hpp:11:0,                  ../src/databaseconnection.cpp:8: /usr/include/sqlite3.h:228:16: warning: forward declaration of ‘struct sqlite3’ [enabled default]  typedef struct sqlite3 sqlite3;                 ^ ../src/databaseconnection.cpp:48:9: note: neither destructor nor class-specific operator delete called, if declared when class defined   delete _database; 

the approach similar person has done http://www.dreamincode.net/forums/topic/122300-sqlite-in-c/

but want make sure free database pointer 'struct sqlite3' class member

your code attempting issue delete _database;, _database has type sqlite3. problem compiler not know sqlite3 is.

you forward declared sqlite3 is, issue delete call requires compile know full definition of sqlite3. did not supply full definition of type.