A.3. Problemas relacionados con la instalación

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 pathname 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 Sección 2.8, “Instalación de MySQL usando una distribución de código fuente”.

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:

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.

On Windows, you can run the server as a Windows service using normal user accounts beginning with MySQL 4.0.17 and 4.1.2. (Older MySQL versions required you to have administrator rights. This was a bug introduced in MySQL 3.23.54.)

On Unix, the MySQL server mysqld can be started and run by any user. However, you should avoid running the server as the Unix root user for security reasons. In order to change mysqld to run as a normal unprivileged Unix user user_name, you must do the following:

If your Unix machine itself isn't secured, you should assign passwords to the MySQL root accounts in the grant tables. Otherwise, any user with a login account on that machine can run the mysql client with a --user=root option and perform any operation. (It is a good idea to assign passwords to MySQL accounts in any case, but especially so when other login accounts exist on the server host.) See Sección 2.9, “Puesta en marcha y comprobación después de la instalación”.

ERROR: Can't find file: 'path/with/filename.frm' (Errcode: 13)

shell> UMASK=384  # = 600 in octal
shell> export UMASK
shell> mysqld_safe &

shell> UMASK_DIR=504  # = 770 in octal
shell> export UMASK_DIR
shell> mysqld_safe &