When you are linking an application program to use the MySQL
client library, you might get undefined reference errors for
symbols that start with mysql_
, such as
those shown here:
/tmp/ccFKsdPa.o: In function `main': /tmp/ccFKsdPa.o(.text+0xb): undefined reference to `mysql_init' /tmp/ccFKsdPa.o(.text+0x31): undefined reference to `mysql_real_connect' /tmp/ccFKsdPa.o(.text+0x57): undefined reference to `mysql_real_connect' /tmp/ccFKsdPa.o(.text+0x69): undefined reference to `mysql_error' /tmp/ccFKsdPa.o(.text+0x9a): undefined reference to `mysql_close'
You should be able to solve this problem by adding
-Ldir_path -lmysqlclient
at the end of your
link command, where dir_path
represents the
path name of the directory where the client library is
located. To determine the correct directory, try this command:
shell> mysql_config --libs
The output from mysql_config might indicate other libraries that should be specified on the link command as well.
If you get undefined reference
errors for
the uncompress
or
compress
function, add
-lz
to the end of your link command and try
again.
If you get undefined reference
errors for a
function that should exist on your system, such as
connect
, check the manual page for the
function in question to determine which libraries you should
add to the link command.
You might get undefined reference
errors
such as the following for functions that don't exist on your
system:
mf_format.o(.text+0x201): undefined reference to `__lxstat'
This usually means that your MySQL client library was compiled on a system that is not 100% compatible with yours. In this case, you should download the latest MySQL source distribution and compile MySQL yourself. See Section 2.3, “MySQL Installation Using a Source Distribution”.
You might get undefined reference errors at runtime when you
try to execute a MySQL program. If these errors specify
symbols that start with mysql_
or indicate
that the mysqlclient
library can't be
found, it means that your system can't find the shared
libmysqlclient.so
library. The fix for
this is to tell your system to search for shared libraries
where the library is located. Use whichever of the following
methods is appropriate for your system:
Add the path to the directory where
libmysqlclient.so
is located to the
LD_LIBRARY_PATH
environment variable.
Add the path to the directory where
libmysqlclient.so
is located to the
LD_LIBRARY
environment variable.
Copy libmysqlclient.so
to some
directory that is searched by your system, such as
/lib
, and update the shared library
information by executing ldconfig
.
Another way to solve this problem is by linking your program
statically with the -static
option, or by
removing the dynamic MySQL libraries before linking your code.
Before trying the second method, you should be sure that no
other programs are using the dynamic libraries.
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