Reason is that static variable init_settings struct is not reset in mysql_library_end. More detailed description below.

Test to reproduce:

mysql_library_init(...)
mysql_library_end()
mysql_library_init(...)
–

In dbug.c there is a static varibale init_done. Once set to TRUE in code_state(), it remains TRUE. In code_state there is an important operations behind it, for example, setting the outfile for struct init_settings.

if init_settings.outfile is NULL server will end up SEGFAULT due to null-pointer reference in dbug.c:_db_flush. Problem is that outfile is set to NULL when mysql_library_end is called in DBUGCloseFile. Thus, once mysql_library_end is called embedded server can't be used anymore because init_settings struct won't be reinitialized.

The ability to use embedded server for several purposes is crucial for gateway, thus, I'd respect your insight on this.