ld cannot find libmysqlclient - mysql

Question

I remember, years ago when I started using mySQL, it was a nightmare to set up things "just so," so that the libraries were found (especially mySQL libraries!). In my case, I believe ldconfig was the tool that sorted things out. Flash forward to 2012 - have just installed a new "primary" system that includes 64-bit Ubuntu 12.04, and I'm in the process of making sure all my sources will compile. Imagine my surprise that I'm back in the same boat with libmysqlclient.
My web searches have revealed much to try, nothing that helps. Along the way, I found this trick: gcc ... mysql_config --cflags --libs - very nice, but that didn't help.
So, for example, the result of:
gcc -D_FILE_OFFSET_BITS=64 `mysql_config --cflags --libs` \
-o check-my-ip \
-s check-my-ip.c ../common/ini-file.c
is
/tmp/ccxAgCqr.o: In function `updateTables':
/usr/local/src/check-my-ip/check-my-ip.c:373: undefined reference to `mysql_init'
/usr/local/src/check-my-ip/check-my-ip.c:374: undefined reference to `mysql_real_connect'
/usr/local/src/check-my-ip/check-my-ip.c:381: undefined reference to `mysql_error'
/usr/local/src/check-my-ip/check-my-ip.c:381: undefined reference to `mysql_errno'
/usr/local/src/check-my-ip/check-my-ip.c:397: undefined reference to `mysql_field_count'
/usr/local/src/check-my-ip/check-my-ip.c:398: undefined reference to `mysql_use_result'
/usr/local/src/check-my-ip/check-my-ip.c:399: undefined reference to `mysql_fetch_row'
/usr/local/src/check-my-ip/check-my-ip.c:419: undefined reference to `mysql_free_result'
/usr/local/src/check-my-ip/check-my-ip.c:422: undefined reference to `mysql_field_count'
/usr/local/src/check-my-ip/check-my-ip.c:429: undefined reference to `mysql_close'
/tmp/ccxAgCqr.o: In function `myQuery':
/usr/local/src/check-my-ip/check-my-ip.c:439: undefined reference to `mysql_query'
/usr/local/src/check-my-ip/check-my-ip.c:441: undefined reference to `mysql_error'
/tmp/ccxAgCqr.o: In function `indexExists':
/usr/local/src/check-my-ip/check-my-ip.c:464: undefined reference to `mysql_field_count'
/usr/local/src/check-my-ip/check-my-ip.c:465: undefined reference to `mysql_use_result'
/usr/local/src/check-my-ip/check-my-ip.c:466: undefined reference to `mysql_fetch_row'
/usr/local/src/check-my-ip/check-my-ip.c:471: undefined reference to `mysql_free_result'
collect2: ld returned 1 exit status
make: *** [check-my-ip] Error 1
Output from mysql_config --cflags --libs is:
-I/usr/include/mysql -DBIG_JOINS=1 -fno-strict-aliasing -g
-L/usr/lib/x86_64-linux-gnu -lmysqlclient -lpthread -lz -lm -lrt -ldl
These are some other commands that may be helpful in diagnosis:
$ ldconfig -p | grep mysql
libmysqlclient.so.18 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18
libmysqlclient.so (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libmysqlclient.so
$ ls -l /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18
lrwxrwxrwx 1 root root 24 Jun 11 10:21 /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18 -> libmysqlclient.so.18.0.0
$ ls -l /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18.0.0
-rw-r--r-- 1 root root 3408136 Jun 11 10:21 /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18.0.0
I did an aptitude search libmysql and noted that there are 37 lines, most of which have the i386 designation (like: libmysqld-pic:i386),
and I notice that there are zero lines with x86_64 (or -64) in that output; is that part of the problem? (Here are those 37 lines)
$ aptitude search libmysql
p libmysql++-dev - MySQL C++ library bindings (development)
p libmysql++-dev:i386 - MySQL C++ library bindings (development)
p libmysql++-doc - MySQL C++ library bindings (documentation and exampl
p libmysql++3 - MySQL C++ library bindings (runtime)
p libmysql++3:i386 - MySQL C++ library bindings (runtime)
p libmysql-cil-dev - MySQL database connector for CLI
p libmysql-diff-perl - module for comparing the table structure of two MySQ
p libmysql-java - Java database (JDBC) driver for MySQL
p libmysql-ocaml - OCaml bindings for MySql
p libmysql-ocaml:i386 - OCaml bindings for MySql
p libmysql-ocaml-dev - OCaml bindings for MySql
p libmysql-ocaml-dev:i386 - OCaml bindings for MySql
v libmysql-ocaml-dev-dnim6:i386 -
v libmysql-ocaml-dev-jygp6 -
v libmysql-ocaml-dnim6:i386 -
v libmysql-ocaml-jygp6 -
p libmysql-ruby - Transitional package for ruby-mysql
v libmysql-ruby:i386 -
p libmysql-ruby1.8 - Transitional package for ruby-mysql
v libmysql-ruby1.8:i386 -
p libmysql-ruby1.9.1 - Transitional package for ruby-mysql
v libmysql-ruby1.9.1:i386 -
p libmysql6.4-cil - MySQL database connector for CLI
i libmysqlclient-dev - MySQL database development files
p libmysqlclient-dev:i386 - MySQL database development files
v libmysqlclient15-dev -
v libmysqlclient15-dev:i386 -
i A libmysqlclient18 - MySQL database client library
p libmysqlclient18:i386 - MySQL database client library
p libmysqlcppconn-dev - MySQL Connector for C++ (development files)
p libmysqlcppconn-dev:i386 - MySQL Connector for C++ (development files)
p libmysqlcppconn5 - MySQL Connector for C++ (library)
p libmysqlcppconn5:i386 - MySQL Connector for C++ (library)
i libmysqld-dev - MySQL embedded database development files
p libmysqld-dev:i386 - MySQL embedded database development files
p libmysqld-pic - MySQL database development files
p libmysqld-pic:i386 - MySQL database development files
Here's the content of /usr/lib/mysql
$ find /usr/lib/mysql
/usr/lib/mysql
/usr/lib/mysql/plugin
/usr/lib/mysql/plugin/qa_auth_client.so
/usr/lib/mysql/plugin/auth.so
/usr/lib/mysql/plugin/qa_auth_server.so
/usr/lib/mysql/plugin/semisync_master.so
/usr/lib/mysql/plugin/libdaemon_example.so
/usr/lib/mysql/plugin/ha_example.so
/usr/lib/mysql/plugin/adt_null.so
/usr/lib/mysql/plugin/auth_test_plugin.so
/usr/lib/mysql/plugin/auth_socket.so
/usr/lib/mysql/plugin/qa_auth_interface.so
/usr/lib/mysql/plugin/semisync_slave.so
/usr/lib/mysql/plugin/mypluglib.so
I don't know what else to try, where else to look, and would appreciate any pointers.

Answer 1

Linker flags should always be specified last:
gcc -D_FILE_OFFSET_BITS=64 `mysql_config --cflags` \
-o check-my-ip \
-s check-my-ip.c ../common/ini-file.c \
`mysql_config --libs`