C programming, Mysql api and CGI under Apache

Forum: Programming and Scripting
Topic: C programming, Mysql api and CGI under Apache
started by: steph291

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Posted by steph291 on Sep. 27 2007,03:04

Hi everyone,
My problem is I cannot communicate with mysql server using
C api and gcc. Every references to mysql functions return
errors.

I have modified my ld.so.conf to include the path to libmysqlclient (/opt/lampp/lib/mysql) then ldconfig.
but it's not helping, please help !!!

titou@server1:~$ gcc meteotest.c
/tmp/ccSjdnBl.o(.text+0x1d): In function `main':
: undefined reference to `mysql_init'
/tmp/ccSjdnBl.o(.text+0x43): In function `main':
: undefined reference to `mysql_connect'
/tmp/ccSjdnBl.o(.text+0x6c): In function `main':
: undefined reference to `mysql_select_db'
/tmp/ccSjdnBl.o(.text+0x7e): In function `main':
: undefined reference to `mysql_close'
/tmp/ccSjdnBl.o(.text+0xa3): In function `main':
: undefined reference to `mysql_query'
/tmp/ccSjdnBl.o(.text+0xb1): In function `main':
: undefined reference to `mysql_use_result'
/tmp/ccSjdnBl.o(.text+0xc5): In function `main':
: undefined reference to `mysql_fetch_row'
/tmp/ccSjdnBl.o(.text+0x10e): In function `main':
: undefined reference to `mysql_close'
collect2: ld returned 1 exit status

here's the source :
#include <stdio.h>
#include "/home/titou/mysql.h"

#define MYSQL_HOST "localhost"
#define MYSQL_DB "meteo"
#define MYSQL_LOGIN "duh!"
#define MYSQL_PASSWD "duh!"

int main() {
       MYSQL mysql;
       MYSQL_RES *result;
       MYSQL_ROW row;

       mysql_init(&mysql);
       if (!mysql_connect(&mysql,MYSQL_HOST,MYSQL_LOGIN,MYSQL_PASSWD)) {
               return -1;
       }
       if (mysql_select_db(&mysql,MYSQL_DB)) {
               mysql_close(&mysql);
               return -1;
       }
       mysql_query(&mysql,"SELECT * FROM meteoraw");
       result = mysql_use_result(&mysql);
       while((row = mysql_fetch_row(result))) {
               printf("%s",row[1]);
               fflush(stdout);
       }
       mysql_close(&mysql);
       return 0;
}

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Posted by ^thehatsrule^ on Sep. 27 2007,03:21

I'm guessing you would need to link the mysql (client) library during linking time (and dependencies)

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Posted by jpeters on Sep. 27 2007,15:29

Quote (^thehatsrule^ @ Sep. 26 2007,23:21)

I'm guessing you would need to link the mysql (client) library during linking time (and dependencies)

Would:

ln -s /opt/lampp/lib/mysql/*.so /usr/lib
 sudo ldconfig

do that, or something else?

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Posted by ^thehatsrule^ on Sep. 27 2007,16:09

No, those are run time static libs.  You'd want to link dev libs i.e. with -l

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Posted by steph291 on Sep. 27 2007,23:42

Thanks Guys !

I'm guessing that I should include "somewhere" the lib
(like in visual studio  with mssql or oracle api under windows)
for gcc calls... but I don't know how
and yes, maybe do a make and link the thing ...

But under unix/linux in console mode, it's a little bit tricky ...
I'm able to build simple CGI in C but I would love to be able
to do the trick with mysql under dsllinux.

I'm looking into this for several weeks and my project is WIP.
thanks for any replies

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