function my_load_defaults() missing in libmariadbclient

[Luc Castermans]

pi@raspberrypi:~/dsm2sql $ cat /etc/debian_version
9.1

package libmariadbclient-dev provides the library libmariadbclient.so

This library should contain a function my_load_defaults() however it appears to be missing.
Below I demonstrate this by showing linker output with and without this library:

pi@raspberrypi:~/dsm2sql $ gcc db.o rs232.o dm.o -lmariadbclient -o dsm2sql
db.o: In function `init':
db.c:(.text+0x4f4): undefined reference to `my_load_defaults'
collect2: error: ld returned 1 exit status

pi@raspberrypi:~/dsm2sql $ gcc db.o rs232.o dm.o -o dsm2sql
db.o: In function `print_error':
db.c:(.text+0xe4): undefined reference to `mysql_errno'
db.c:(.text+0xf0): undefined reference to `mysql_error'
db.o: In function `do_connect':
db.c:(.text+0x14c): undefined reference to `mysql_init'
db.c:(.text+0x1a4): undefined reference to `mysql_real_connect'
db.o: In function `do_disconnect':
db.c:(.text+0x1f4): undefined reference to `mysql_close'
db.o: In function `process_result_set':
db.c:(.text+0x2a0): undefined reference to `mysql_num_fields'
db.c:(.text+0x2c8): undefined reference to `mysql_fetch_row'
db.c:(.text+0x2e0): undefined reference to `mysql_errno'
db.c:(.text+0x30c): undefined reference to `mysql_num_rows'
db.o: In function `process_query':
db.c:(.text+0x374): undefined reference to `mysql_query'
db.c:(.text+0x3b4): undefined reference to `mysql_store_result'
db.c:(.text+0x3cc): undefined reference to `mysql_field_count'
db.c:(.text+0x3f8): undefined reference to `mysql_affected_rows'
db.c:(.text+0x438): undefined reference to `mysql_free_result'
db.o: In function `init':
db.c:(.text+0x4d4): undefined reference to `my_init'
db.c:(.text+0x4f4): undefined reference to `my_load_defaults'
db.c:(.text+0x75c): undefined reference to `get_tty_password'
db.o: In function `main':
db.c:(.text+0x8ec): undefined reference to `mysql_server_init'
db.c:(.text+0xa38): undefined reference to `mysql_server_end'
collect2: error: ld returned 1 exit status
pi@raspberrypi:~/dsm2sql $

[Luc Castermans (luc-castermans-q)]

Note: before I compiled the same program for MySQL. I used package libmysqlclient-dev. In this case the function is available in this library.

[peter green (plugwash)]

Frankly I don't have a clue about this, i'm not even sure whether it is a bug or a user error.

[Robie Basak (racb)]

I suspect this is due to some distinction between libmysqlclient18, libmysqlclient20, and MariaDB's "drop-in" replacement of libmysqlclient18 (which in Debian we call libmariadbclient18 to disambiguate).

I don't believe MariaDB ever went beyond attempted compatibility against MySQL 5.6 (ie. libmysqlclient18's API). When you try against libmysqlclient-dev, you're probably building against MySQL 5.7 which is a different API revision.

I don't know if this is a bug or not either. It depends on whether upstream MariaDB expects to be shipping a my_load_defaults function in their API that they forked from libmysqlclient18 but didn't rename upstream.