Adding source to C project to include mysql.h = new errors

true_atlantis · 07-14-2009, 10:11 AM

I am trying to modify the source code of a C application (quagga) in order to insert data into a mysql table. I have added 2 new source files to the source (neto_mysql, neto_trend) which in turn use mysql.h. I have also modified the Makefile.am file to include the /usr/include/mysql directory.

When trying to compile, i get the following error. What am I missing? I have minimal experience with formal C applications like this. I feel like I may also have to include the mysql.h file in the libbgp? I dont understand why it cant find the mysql functions...

Code:

if gcc -DHAVE_CONFIG_H -DSYSCONFDIR=\"/usr/local/etc/\" -I. -I. -I.. -I.. -I.. -I../lib  -I/usr/include/mysql/   -fPIE -Os -fno-omit-frame-pointer -g -std=gnu99 -Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual -MT bgp_main.o -MD -MP -MF ".deps/bgp_main.Tpo" -c -o bgp_main.o bgp_main.c; \
then mv -f ".deps/bgp_main.Tpo" ".deps/bgp_main.Po"; else rm -f ".deps/bgp_main.Tpo"; exit 1; fi
/bin/sh ../libtool --mode=link --tag=CC gcc -fPIE -Os -fno-omit-frame-pointer -g -std=gnu99 -Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual -pie  -o bgpd  bgp_main.o libbgp.a ../lib/libzebra.la  -lm -lcrypt  
libtool: link: gcc -fPIE -Os -fno-omit-frame-pointer -g -std=gnu99 -Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual -pie -o .libs/bgpd bgp_main.o  libbgp.a ../lib/.libs/libzebra.so -lm -lcrypt -Wl,-rpath -Wl,/usr/local/lib
libbgp.a(neto_trend.o)(.text+0x8a): In function `neto_trend_insert':
/opt/quagga/bgpd/neto_trend.c:28: undefined reference to `itoa'
libbgp.a(neto_mysql.o)(.text+0x16): In function `neto_mysql_init':
/opt/quagga/bgpd/neto_mysql.c:14: undefined reference to `mysql_init'
libbgp.a(neto_mysql.o)(.text+0x41):/opt/quagga/bgpd/neto_mysql.c:21: undefined reference to `mysql_real_connect'
libbgp.a(neto_mysql.o)(.text+0x4e):/opt/quagga/bgpd/neto_mysql.c:22: undefined reference to `mysql_error'
libbgp.a(neto_mysql.o)(.text+0x81): In function `neto_mysql_execute':
/opt/quagga/bgpd/neto_mysql.c:31: undefined reference to `mysql_exec_sql'
libbgp.a(neto_mysql.o)(.text+0x8d):/opt/quagga/bgpd/neto_mysql.c:32: undefined reference to `mysql_error'
libbgp.a(neto_mysql.o)(.text+0xbd): In function `neto_mysql_destroy':
/opt/quagga/bgpd/neto_mysql.c:39: undefined reference to `mysql_close'
collect2: ld returned 1 exit status
make[2]: *** [bgpd] Error 1
make[2]: Leaving directory `/opt/quagga/bgpd'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/opt/quagga'
make: *** [all] Error 2

norobro · 07-15-2009, 11:57 AM

Code:

/opt/quagga/bgpd/neto_trend.c:28: undefined reference to `itoa'

indicates that you don't have stdlib.h included.

Try putting the following in your source:

Code:

#include <stdlib.h>
#include <mysql/mysql.h>

orgcandman · 07-15-2009, 12:33 PM

you probably also need to add

-lmysqlclient

to the final link command-line.

true_atlantis · 07-15-2009, 12:41 PM

I am still getting the same errors with the include lines - where is the 'final link command-line'?

norobro · 07-15-2009, 12:57 PM

no comprende.

Can you give us some context?

dwhitney67 · 07-15-2009, 01:14 PM

Quote:

Originally Posted by true_atlantis

I am still getting the same errors with the include lines - where is the 'final link command-line'?

Why don't you try to build your application on the command line?

The general format is:

Code:

gcc -c File1.c -o File1.o
gcc -c File2.c -o File2.o
...

gcc File1.o File2.o ... -o MyApp -lmysqlclient

Try something like this, then post the results. Only once you comprehend the steps to build an application should you rely on an IDE to do the work for you... merely my opinion.

norobro · 07-15-2009, 01:27 PM

Quote:

Originally Posted by orgcandman

to the final link command-line.

I see where you got that now. I'm a little slow.

For the "mysql" errors you probably need to install "libmysqlclient-dev"

Are you still getting the "undefined reference to itoa"?

true_atlantis · 07-27-2009, 03:06 PM

This is a redhat 4 box, and I can see that the mysql headers are there:

Code:

[root@zebra quagga]# ls /usr/include/mysql/
chardefs.h  m_ctype.h    my_dir.h     my_no_pthread.h  mysql_embed.h    my_xml.h     rlshell.h      sslopt-longopts.h
errmsg.h    m_string.h   my_getopt.h  my_pthread.h     mysql.h          raid.h       rltypedefs.h   sslopt-vars.h
history.h   my_alloc.h   my_global.h  my_semaphore.h   mysql_time.h     readline.h   sql_common.h   tilde.h
keycache.h  my_config.h  my_list.h    mysql_com.h      mysql_version.h  rlmbutil.h   sql_state.h    typelib.h
keymaps.h   my_dbug.h    my_net.h     mysqld_error.h   my_sys.h         rlprivate.h  sslopt-case.h  xmalloc.h

The Makefile.am includes this directory:
INCLUDES = @INCLUDES@ -I.. -I$(top_srcdir) -I$(top_srcdir)/lib @SNMP_INCLUDES@ -I/usr/include/mysql/

The source file tries to include them via:

Code:

#include <mysql/mysql.h>

These are the errors im currently getting:

Code:

libtool: link: gcc -fPIE -Os -fno-omit-frame-pointer -g -std=gnu99 -Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual -pie -o .libs/bgpd bgp_main.o  libbgp.a ../lib/.libs/libzebra.so -lm -lcrypt -Wl,-rpath -Wl,/usr/local/lib
libbgp.a(comcast_trend.o)(.text+0x8a): In function `comcast_trend_insert':
/opt/quagga/bgpd/comcast_trend.c:29: undefined reference to `itoa'
libbgp.a(comcast_mysql.o)(.text+0x16): In function `comcast_mysql_init':
/opt/quagga/bgpd/comcast_mysql.c:15: undefined reference to `mysql_init'
libbgp.a(comcast_mysql.o)(.text+0x41):/opt/quagga/bgpd/comcast_mysql.c:22: undefined reference to `mysql_real_connect'
libbgp.a(comcast_mysql.o)(.text+0x4e):/opt/quagga/bgpd/comcast_mysql.c:23: undefined reference to `mysql_error'
libbgp.a(comcast_mysql.o)(.text+0x81): In function `comcast_mysql_execute':
/opt/quagga/bgpd/comcast_mysql.c:32: undefined reference to `mysql_exec_sql'
libbgp.a(comcast_mysql.o)(.text+0x8d):/opt/quagga/bgpd/comcast_mysql.c:33: undefined reference to `mysql_error'
libbgp.a(comcast_mysql.o)(.text+0xbd): In function `comcast_mysql_destroy':
/opt/quagga/bgpd/comcast_mysql.c:40: undefined reference to `mysql_close'
collect2: ld returned 1 exit status
make[2]: *** [bgpd] Error 1
make[2]: Leaving directory `/opt/quagga/bgpd'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/opt/quagga'
make: *** [all] Error 2

I cant really build this whole application via command line because there are about 200 source files...

There still are errors for 'itoa' and I do have this:
#include <stdlib.h>

Thanks for all the help!

paulsm4 · 07-27-2009, 03:28 PM

Hi -

If your mysql files are here

Quote:

/usr/include/mysql/*.h

... and your source says

Quote:

#include <mysql/mysql.h>

Then your -I needs to be

Quote:

gcc -I/usr/include (not "-I/usr/include/mysql")

Of course all this begs the question why your compiler isn't looking in "/usr/include" in the first place (for example, why didn't it find "itoa()", if you #include'd <stdlib.h>?)

SUGGESTION:
Add a "hello world" target to your makefile, and verify that you can compile, link and execute "hello world" first.

If this is a cross-compile scenario, review your toolchain install/configuration. If this is just a native, vanilla "gcc", consider re-installing.

'Hope that helps .. PSM

PS:
This link might also help:
http://gcc.gnu.org/onlinedocs/gccint/Header-Dirs.html

PPS:
If this is the native "gcc", how did you install it? Was gcc automatically installed when you installed Linux? Did you install gcc from the .rpm? Or did you install gcc some other way?

true_atlantis · 07-27-2009, 05:05 PM

Everything was installed via RPM's. This is strange though, a simple heloworld will work, but this fails:

Code:

[root@zebra tmp]# cat helloworld.c 
#include <stdio.h>
#include <stdlib.h>

int main(){
        char x[10];
        itoa(10,x,10);
        printf("test %s", x);
}
[root@zebra tmp]# gcc helloworld.c 
/tmp/cc4BVp9I.o(.text+0x28): In function `main':
: undefined reference to `itoa'
collect2: ld returned 1 exit status

raconteur · 07-27-2009, 05:15 PM

IIRC, itoa() is a non-ANSI function introduced by Windows.
It is implemented in some versions of gcc, but no recent ones (I think -- at least it doesn't appear anywhere on my linux boxen).
It is redundant, however -- the printf(), sprintf(), and similar functions perform number-to-string conversions.

orgcandman · 07-28-2009, 08:44 AM

Quote:

Originally Posted by true_atlantis

The Makefile.am includes this directory:
INCLUDES = @INCLUDES@ -I.. -I$(top_srcdir) -I$(top_srcdir)/lib @SNMP_INCLUDES@ -I/usr/include/mysql/

This is probably incorrect. If you're using <mysql/mysql.h> and there is a mysql/mysql.h directory in /usr/include, you're all set. The compiler searches for it by default.

Quote:

Originally Posted by true_atlantis

These are the errors im currently getting:

Code:

libtool: link: gcc -fPIE -Os -fno-omit-frame-pointer -g -std=gnu99 -Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual -pie -o .libs/bgpd bgp_main.o  libbgp.a ../lib/.libs/libzebra.so -lm -lcrypt -Wl,-rpath -Wl,/usr/local/lib
libbgp.a(comcast_trend.o)(.text+0x8a): In function `comcast_trend_insert':
/opt/quagga/bgpd/comcast_trend.c:29: undefined reference to `itoa'
libbgp.a(comcast_mysql.o)(.text+0x16): In function `comcast_mysql_init':
/opt/quagga/bgpd/comcast_mysql.c:15: undefined reference to `mysql_init'
libbgp.a(comcast_mysql.o)(.text+0x41):/opt/quagga/bgpd/comcast_mysql.c:22: undefined reference to `mysql_real_connect'
libbgp.a(comcast_mysql.o)(.text+0x4e):/opt/quagga/bgpd/comcast_mysql.c:23: undefined reference to `mysql_error'
libbgp.a(comcast_mysql.o)(.text+0x81): In function `comcast_mysql_execute':
/opt/quagga/bgpd/comcast_mysql.c:32: undefined reference to `mysql_exec_sql'
libbgp.a(comcast_mysql.o)(.text+0x8d):/opt/quagga/bgpd/comcast_mysql.c:33: undefined reference to `mysql_error'
libbgp.a(comcast_mysql.o)(.text+0xbd): In function `comcast_mysql_destroy':
/opt/quagga/bgpd/comcast_mysql.c:40: undefined reference to `mysql_close'
collect2: ld returned 1 exit status
make[2]: *** [bgpd] Error 1
make[2]: Leaving directory `/opt/quagga/bgpd'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/opt/quagga'
make: *** [all] Error 2

This is not a file inclusion error. It's a linker error. As I said in my previous post, you need to add -lmysqlclient to your linking line.

As far as itoa goes, you can use snprintf to do the job

Code:

#include <stdio.h>

void my_itoa(int i, char *a, int base)
{
    switch(base)
    {
        default:
        case 10:
            sprintf(a, "%d", base);
            break;
        case 16:
            sprintf(a, "%x", base);
            break;
         /*handle other bases later...*/
    }
}

That hasn't been tested, but I think that it should suffice as a way to emulate what you're looking for.

-Aaron

globaltree · 09-23-2009, 04:00 PM

orgcandman is correct: the "undefined reference" errors are related to the linking line:

i don't know if this thread is solved, and as it is clear that some time has elapsed, it may no longer be active... however, working from the tutorial at http://www.zetcode.com/tutorials/mysqlcapitutorial/ I was encountering the same "undefined reference" errors to the mysql functions, like mysql_init and mysql_real_connect...

raconteur cleared up that business with itoa(), but to make sure that the solution to the "undefined references" is clearly stated, I was able to use the command

Code:

mysql_config --cflags --libs

on my system, and it returned

Code:

-I/usr/include/mysql -march=i486 -mtune=i686
-L/usr/lib/mysql -lmysqlclient -lz -lcrypt -lnsl -lm -L/usr/lib -lssl -lcrypto

.

I then added these results to the linker line and the "undefined references" errors went away and my application compiled successfully:

Code:

gcc mysqlapp.c -o mysqlapp -I/usr/include/mysql -march=i486 -mtune=i686
-L/usr/lib/mysql -lmysqlclient -lz -lcrypt -lnsl -lm -L/usr/lib -lssl -lcrypto

I noticed that orgcandman's suggestion of "-lmysqlclient" was part of mysql_config's return, and maybe that's all I needed to solve the "undefined references" problem, but I've been using the the other flags as well, as they are pertinent to what mysql_config found on my slackware 12.2 system. However, it would probably have found different output with different distros and hardware, so be sure to execute mysql_config on your own system, and not copy the output from this thread.