If, after an upgrade, you experience problems with compiled client
programs, such as
Commands out of sync or
unexpected core dumps, the programs were probably compiled using
old header or library files. In this case, check the date of the
mysql.h header file and
libmysqlclient.a library used for compilation
to verify that they are from the new MySQL distribution. If not,
recompile the programs with the new headers and libraries.
Recompilation might also be necessary for programs compiled
against the shared client library if the library major version
number has changed (for example, from
The major shared client library version determines compatibility.
(For example, for
major version is 18.) Libraries shipped with newer versions of
MySQL are drop-in replacements for older versions that have the
same major number. As long as the major library version is the
same, you can upgrade the library and old applications should
continue to work with it.
Undefined-reference errors might occur at runtime when you try to
execute a MySQL program. If these errors specify symbols that
mysql_ or indicate that the
libmysqlclient library cannot be found, it
means that your system cannot find the shared
libmysqlclient.so library. The solution to
this problem is to tell your system to search for shared libraries
in the directory where that library is located. Use whichever of
the following methods is appropriate for your system:
Add the path of the directory where
libmysqlclient.sois located to the
On macOS, add the path of the directory where
libmysqlclient.dylibis located to the
Copy the shared-library files (such as
libmysqlclient.so) to some directory that is searched by your system, such as
/lib, and update the shared library information by executing
ldconfig. Be sure to copy all related files. A shared library might exist under several names, using symlinks to provide the alternate names.
If the application is linked to the embedded server library,
runtime error messages indicate the
libmysqlclient library, but the
solution to the problem is the same as just described.