How to statically link sqlite3 + extension functions into a C / C++ application?

I already build sqlite3.c into my application and extension-functions.c (hxxps://www.sqlite.org/contrib) into a shared library and it worked fine, but for the project I'm working on I have to statically link sqlite3 + extension functions into a C++ application. I already read a lot of sources to this topic, but I cannot get it working.

Minimal example (test.cc):

#include "sqlite3.h"
#include<cstdlib>

void sqlite3_extension_functions_init(void);
// typedef struct sqlite3_api_routines sqlite3_api_routines;
// int sqlite3_extension_functions_init(sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi);

int main(int argc,char *argv[]) {
    //  sqlite3_auto_extension( (void(*)(void))sqlite3_extension_functions_init );
    sqlite3_auto_extension( sqlite3_extension_functions_init );

    sqlite3 *database_;
    sqlite3_open_v2("test.db", &database_, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL);

    sqlite3_close_v2(database_);

    return 0;
}

Build command:

gcc -o test sqlite3.c extension_functions.c test.cc -lpthread -lm -ldl -DSQLITE_CORE

(-DSQLITE_CORE no influence ?)

Errors:

/tmp/ccPfaDLE.o: In function `main':
test.cc:(.text+0x10): undefined reference to `sqlite3_extension_functions_init()'
collect2: ld returned 1 exit status

using commented lines instead:

/tmp/ccrs9B0K.o: In function `main':
test.cc:(.text+0x10): undefined reference to `sqlite3_extension_functions_init(sqlite3*, char**, sqlite3_api_routines const*)'
collect2: ld returned 1 exit status

• sqlite3.c, sqlite3.h, sqlite3ext.h from SQLite 3.8.6


• extension_functions.c from http://ift.tt/1w2MjDw (renamed extension-functions.c) -> modified for static linking according to http://ift.tt/1w2MkaJ and renamed int sqlite3_extension_init() into int sqlite3_extension_functions_init()

Other sources I used:

• hxxp://books.google.de/books?vid=ISBN1449399649&q=209


• hxxps://www.sqlite.org/loadext.html


• hxxp://stackoverflow.com/a/1295765

Maybe I'm blind, but the function prototype is given in test.cc and the function definition in extension_functions.c. Has anybody an idea what is wrong with this code example? Thank you in advance for your help.(I'm sorry for the hxxp:// links, but I'm not allowed to post more than two links)