comp_err creates the errmsg.sys file that is used by mysqld to determine the error messages to display for different error codes. comp_err normally is run automatically when MySQL is built. It compiles the errmsg.sys file from text-format error information in MySQL source distributions:
As of MySQL 8.0.19, the error information comes from the messages_to_error_log.txt and messages_to_clients.txt files in the share directory.
For more information about defining error messages, see the comments within those files, along with the errmsg_readme.txt file.
Prior to MySQL 8.0.19, the error information comes from the errmsg-utf8.txt file in the sql/share directory.
comp_err also generates the mysqld_error.h, mysqld_ername.h, and mysqld_errmsg.h header files.
Invoke comp_err like this:
comp_err [options]
comp_err supports the following options.
--help, -?
Display a help message and exit.
--charset=, dir_name-C dir_name
The character set directory. The default is ../sql/share/charsets.
--debug=, debug_options-# debug_options
Write a debugging log. A typical debug_options string is d:t:O,. The default is file_named:t:O,/tmp/comp_err.trace.
--debug-info, -T
Print some debugging information when the program exits.
--errmsg-file=, file_name-H file_name
The name of the error message file. The default is mysqld_errmsg.h. This option was added in MySQL 8.0.18.
--header-file=, file_name-H file_name
The name of the error header file. The default is mysqld_error.h.
--in-file=, file_name-F file_name
The name of the input file. The default is ../share/errmsg-utf8.txt.
This option was removed in MySQL 8.0.19 and replaced by the --in-file-errlog and --in-file-toclient options.
--in-file-errlog=, file_name-e file_name
The name of the input file that defines error messages intended to be written to the error log. The default is ../share/messages_to_error_log.txt.
This option was added in MySQL 8.0.19.
--in-file-toclient=, file_name-c file_name
The name of the input file that defines error messages intended to be written to clients. The default is ../share/messages_to_clients.txt.
This option was added in MySQL 8.0.19.
--name-file=, file_name-N file_name
The name of the error name file. The default is mysqld_ername.h.
--out-dir=, dir_name-D dir_name
The name of the output base directory. The default is ../sql/share/.
--out-file=, file_name-O file_name
The name of the output file. The default is errmsg.sys.
--version, -V
Display version information and exit.