Why do I keep getting undefined symbols when compiling a simple mysql c application on MAC OSX?

I'm using MAC OSX and trying to write a 'test' msyql app that just tests the connection to a local database:

#include <my_global.h>
#include <mysql.h>


int main(void)
{
    MYSQL mysql;

    mysql_init(&mysql);
    mysql_options(&mysql, MYSQL_READ_DEFAULT_GROUP, "examplemysql");
    if(!mysql_real_connect(&mysql, "localhost", "someuser", "somepassword", "sampledb", 0, NULL, 0))
    {
        fprintf(stderr, "Failed to connect to database: Error: %s\n", mysql_error(&mysql));
    }

}

I compile using the command: g开发者_StackOverflow社区cc -I/usr/local/mysql/include -L/usr/local/mysql/lib mysql.c

I get the following errors

Undefined symbols

"_mysql_options", referenced from:

_main in cceohP7E.o

"_mysql_real_connect", referenced from:

_main in cceohP7E.o

"_mysql_init", referenced from:

_main in cceohP7E.o

"_mysql_error", referenced from:

_main in cceohP7E.o

ld: symbol(s) not found

collect2: ld returned 1 exit status

I'm no C/Unix expert, but I want to learn. I know I have a 64-bit architecture running here. Can this be an issue? Let me know what I'm doing wrong.

Thanks.

---

As the others have mentioned, you're missing the library. Fortunately, MySQL makes this easy via the command line's mysql_config:

gcc `mysql_config --include` mysql.c `mysql_config --libs`

---

You need to link in the shared library libmysql.so, those are linker errors with trying to find other symbols.

Something like this...

gcc -I/usr/local/mysql/include -L/usr/local/mysql/lib mysql.c -lmysql

---

I'm updating this answer for OSX Lion and for anyone searching for this... just because it was difficult for me.

The mysql_config is one option, or specifying the gcc flags yourself is another but without the right C connector, it all fails.

I'm on Lion 10.7.4 Macbook air and I downloaded mysql-connector-c-6.0.2-osx10.5-x86-64bit.tar which I got from http://ftp.dc.aleron.net/pub/mysql/Connector-C/

untar and unzip all the files and copy the respective /bin /include and /lib files to the respective /usr/local/bin, /usr/local/include and /usr/lical/lib directories as root

then I used gcc -o mysqlapp mysqlapp.c -L /usr/local/lib -l mysqlclient -lz -I /usr/local/include

mysqlapp.c uses mysql.h and everything compiles and runs fine. The connector I originally downloaded from www.mysql.com would not work correctly. I'm not sure what happened with that one.