MySQL Bugs: #25535: load_defaults() no longer included by mysql.h

Bug #25535	load_defaults() no longer included by mysql.h
Submitted:	10 Jan 2007 20:17	Modified:	20 May 2009 20:26
Reporter:	Hartmut Holzgraefe	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: C API (client library)	Severity:	S4 (Feature request)
Version:	5.1.12 and up	OS:	Any (*)
Assigned to:		CPU Architecture:	Any

Description:
in rev 1.106 of include/mysql_com.h (cset 1.2119.593.1) the prototype 
of load_deafaults() (amongst others) was removed with the commit comment

  "Removed duplicate declarations, my_sys.h should be used instead"

This leads to compile errors in applications that just include "mysql.h" which should usually be sufficient. 

Even worse: my_sys.h adds lots of extra header file dependencies, so simply adding it to the includes of application source that so far only included mysql.h will lead to tons of extra compile errors.

How to repeat:
a sample source project will be attached ...

Suggested fix:
put the load_defaults() prototype back into mysql_com.h and remove it from my_sys.h instead (if that is possible without breaking other things).

test project

Attachment: bug25535-0.1.tar.bz2 (application/x-tar, text), 188.92 KiB.

The attached test project tries to build two binaries "without_my_sys" and "with_my_sys" that just consist of a load_defaults call.

with "configure --with-mysql=/path/to/mysql-5.0" the without version that just includes mysql.h works fine, only the with_my_sys build fails due to the addition of

  #include <my_sys.h>

when configuring against 5.1 instead both builds fail for anything after 5.1.11

Dear Hartmut,
this function is not documented, has no reserved name prefix, and therefore should not be exported by the client API.
Moreover, mysql.h is a header for MySQL client library, whereas load_defaults belongs to mysys/ library. If you would like to use this function from mysys, you should include the corresponding header.
Long term we may remove or rename any function that is currently declared in a  public header but is not documented and/or does not start with my_ or mysql_.
Please feel free to reopen this bug if you have further feedback.

>this function is not documented, has no reserved name prefix, 
> and therefore should not be exported by the client API.

this function is used by all cluster tools to fetch cluster
configuration from the [mysql_cluster] section in my.cnf,
especially the connect_string that is essential for all
cluster operations

IMHO it is perfectly valid to expect to be able to use the
same mechanism for any other ndbapi applications, to have
them behave like the distributed ndbapi tools as much as
possible

> Moreover, mysql.h is a header for MySQL client library, 
> whereas load_defaults belongs to mysys/ library. If you 
> would like to use this function from mysys,
> you should include the corresponding header.

No problem with that *if* just including my_sys.h in addition
to mysql.h would work, which it doesn't. See the attached
test project, adding "#include <my_sys.h>" produces *lots*
of compile errors ...

> Long term we may remove or rename any function that is 
> currently declared in a public header but is not documented
> and/or does not start with my_ or mysql_.

I'm all for having proper name prefixes, but access to the
[mysql_cluster] section in my.cnf section is essential for 
ndbapi based tools, and it is usefull for applications using
mysqlclient, too, e.g to fetch the default socket file name 
from the my.cnf [client] section (this would have helped to
prevent *tons* of PHP bug reports caused by PHPs bundled 
libmysqlclient being compiled with different defaults than
the local mysql installation ...)

> Please feel free to reopen this bug if you have further feedback.

Done, reopened as verified high priority feature request

This is also documented in Paul's MySQL book, and it's the only way for MySQL clients to get a mysql-compatible behaviour regardning command line options and options files (getting options from my.cnf).

suggestion: rename it to my_load_defaults (to match my_getopt) or mysql_load_defaults, and add back to mysql.h

The same treatment should be given to any other function from
the client libs that people need to use when the write MySQL programs.
handle_options() is such an instance. Rename to my_handle_options()
or some such?

Hello Sir,
Sir I want to use load_default() in my client program MySQL-4.1.20 the program gets compiled without error, but when executed the program does not take data from .my.cnf file.
Platform is FC4 
Sir if u can help on it plz do so,
yours truly,
Deepika

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/39244

ChangeSet@1.2614, 2007-12-04 22:32:08+03:00, kostja@bodhi.(none) +1 -0
  Fix Bug#25535 "load_defaults() no longer included by mysql.h" by
  making sure that load_defaults can be made available by including
  my_sys.h. Note, if one includes both my_sys.h and mysql.h, my_sys.h
  got to go first (this is how mysql.h is written).

This patch is out-of-date now that load_defaults() has been renamed to my_load_defaults().

Checked on latest 5.1 and see that load_defaults is declared in my_sys.h and removed from mysql.h.