Cannot connect to MariaDB with ZConnection Component under macOS
lazarus / 16-Databases

----------------------------------------------------------------------
Tomki · 2023-06-05 11:28

Hello all
after a while break I rediscovered Lazarus and try to port older
Delphi projects (still from Windows) to Lazarus under macOS and
modernize them.
I want to create a client for a MariaDB running on a QNAP NAS.
The DB is set up and I can access it with myPHPAdmin and mySQL
Workbench ... so far so good.
I am using a Mac Pro (Intel macOS 12) and a MacBook (M1, macOS 13). I
can also access a few other Macs (with Intel CPU) to test things.
Now what happens is this. For starters, I simply try to connect to
MariaDB via a ZConnection component of ZEOS. On the Mac Pro, this
works without any grumbling. Same project on the MacBook (same Lazarus
environment, mySQL installed) and I always get the same error:
"libmysq|client.dylib found but could not be loaded. Check compile-
target and library compatibility!. "
I am still in the IDE - nothing compiled. On Mac Pro it works - on all
other Macs the error comes.  :oops:
The lib is available. I also copied it to the project folder and also
referenced the lib directly with the "LibraryLocation" property. When
trying it out, I tried different versions of the mySQLClient.dylib.
Always the same error on all Macs except the Mac Pro!!! I can't find
any help in the various wikis or forums. Does anyone here have any
ideas?
I have attached a screenshot.
Thanks in advance!

----------------------------------------------------------------------
marsupilami79 · 2023-06-06 10:51

Hello Tomki,

Quote from: Tomki on June 05, 2023, 01:28:05 pm"libmysq|client.dylib
found but could not be loaded. Check compile-target and library
compatibility!. "
Zeos will generate that exception if it can find the library but
cannot load it for some reason. What happens if you do something like
tis:
Code: [Select]procedure TestLibrayLoading;
var
  Handle: THandle:
begin
  Handle :=
LoadLibrary(PChar('/Users/thomas/Documents/work/Pascal/sql-
test/libmysqlclient.21.dylib'));
  if Handle = 0 then
    RaiseLastOsError
  else
    ShowMessage('Library loaded successfully.');
end;
Maybe this gives some more information on what happens. Also you might
want to check if all dependencies of libmysqlclient.21.dylib are
available. On Linux one can use ldd to check which other libraries are
necessary.

Best regards,

Jan

----------------------------------------------------------------------
Tomki · 2023-06-07 07:28

Thanks Jan
I tried and attached you can see the result. But I swear: the file is
there!
Regards
Thomas

----------------------------------------------------------------------
Zvoni · 2023-06-07 07:32

is the dylib just copied over, or is it compiled for M1 (ARM)?
What's YOUR Compile-Target in your Project?

----------------------------------------------------------------------
Tomki · 2023-06-07 07:33

Different question:
I did not only copy the libmysqlclient.21.dylib into the project
directory, but all of the *.dylib files. Is there anything else which
I need to do?
In a different scenario I pointed the LibraryLocation of the
TZConnection component to the /usr/local/ folder in which the mySQL
libs were placed at installation.
/usr/local/mysql-8.0.33-macos13-x86_64/lib/libmysqlclient.21.dylib
In this case it works! But I cannot make an application bundle, if it
doesn't work if the lib location is different!?
Thomas

----------------------------------------------------------------------
Tomki · 2023-06-07 07:35

Quote from: Zvoni on June 07, 2023, 09:32:58 amis the dylib just
copied over, or is it compiled for M1 (ARM)?
What's YOUR Compile-Target in your Project?

it's just copied from the install directory of mySQL! See above
addition...

----------------------------------------------------------------------
Tomki · 2023-06-07 07:38

Quote from: Zvoni on June 07, 2023, 09:32:58 amis the dylib just
copied over, or is it compiled for M1 (ARM)?
What's YOUR Compile-Target in your Project?

compile targets are left on "default".
However, this problem persists on M1 and on Intel based Macs...
The initial setup is identical (as far as I can judge this)

----------------------------------------------------------------------
Zvoni · 2023-06-07 07:42

Access-Rights on the dylib itself?
I don't remember anymore on *Nix if you have to set "executable"-Flag
and/or Access-Flags if you copy a file from a "protected" Folder

----------------------------------------------------------------------
Tomki · 2023-06-07 07:46

I look at the information about both files. See attached.
Sorry, but I am not an expert on "system level" 
Difference appears to be the "owner"

----------------------------------------------------------------------
Tomki · 2023-06-07 08:35

Zvoni, now I think it must have to do with access rights or something
like that deep in the system which I don't understand 
I copied the lib libmysqlclient.21.dylib from another application into
my project folder. I found out that all the libs are contained in the
"Frameworks" folder of the mySQLWorkbench application. So I used this
one and now I have the following effect:
I point the LibraryLocation to this lib file which I copied from the
mySQLWorkbench.app/Frameworks and in the Lazarus Designer I get the
same old error message (file found, but can't load) - but if I compile
the project (no other change) it work's without error during
runtime!?!?!
To me there is no difference in the access rights of the newly copied
file, but obviously there must be some difference in the background.
So now, what is the difference and why does it not work in Designtime
but in runtime?

----------------------------------------------------------------------
TRon · 2023-06-07 08:42

Quote from: Tomki on June 07, 2023, 10:35:23 amSo now, what is the
difference and why does it not work in Designtime but in runtime?
It is possible that you installed Lazarus as another user/owner. Some
people install/run Lazarus as admin/root/userX (don't ask me why)
while you "the normal user" invoked the compiled application from the
OS (not through Lazarus). That also applies to/for mariaDB (admin
users can do more/other things with the DB manager).

There is a distinct difference in such cases (user access rights).
Unfortunately I am not familiar with the platform to such extend that
I can make any (additional) suggestions.

Does MacOS has something like the strace utility for Linux ?

----------------------------------------------------------------------
Tomki · 2023-06-07 09:01

Hi TRon
Thank's for your reply, but no, not that I know of

----------------------------------------------------------------------
TRon · 2023-06-07 09:10

Quote from: Tomki on June 07, 2023, 11:01:32 amHi TRon
Thank's for your reply, but no, not that I know of 
Seems it is called dtruss ? or install strace using brew ?

see also: https://stackoverflow.com/questions/73724074/how-to-call-an-
equivalent-command-to-strace-on-mac-ideally-from-python (ignore the
python parts and what the original question is asking: look at the
suggestion for utilities/workarounds to use a trace tool such as
strace, dtrace, exesnoop etc though your mileage might vary due to
security reasons).

edit: the point in asking is that a utility like strace is able to
show you what the application is doing at runtime (loading
files/libraries) and what other files the executable drags in during
execution (also indirect loading of additional
libraries/dependencies/configuration files etc) and report if that
succeeded and/or failed. Even something like a tool like a dll
dependency walker (on Windows) is able to show the dependencies a
library has. It would be able to better pinpoint the issue you seem to
be facing. Unless ofc. someone has a better idea ?

----------------------------------------------------------------------
Tomki · 2023-06-17 17:00

I now tried everything … install_name_tool …. otool … as described and
still no success.
Different approach: Did anyone build a macOS app with mysql and a
correspomding application bundle? Can any tell me what to do to make
the app connect to a mysql (or mariadb server)?
I guess I‘ll open a new threat woth this question…