QMYSQL driver not loaded on mac

[Hasan Vaez]

Tried to use the following command and problem solved.
install_name_tool -change /opt/local/lib/mysql55/mysql/libmysqlclient.18.dylib /usr/local/mysql/lib/libmysqlclient.20.dylib /Users/hasan/Qt5.9.1/5.9.1/clang_64/plugins/sqldrivers/libqsqlmysql.dylib

The thing I am worry about is when I will face to problem as we tricked to Qt to use libqslmysql.20.dylib instead of the the one in version 18 (libmysqlclient.18.dylib).
Mainly the problem is solved but it should not be OK. I am looking for a way to solve the problem in a correct way and do not want to use MACPORTS for installing the QMYSQL module. MACPORTS is a good installation package, but its size is more than 1GB in HDD and I'd prefer to use certified sourced like mysql.com website and qt.io website and so on...

[SGaist]

Then just install the package you want from whatever source suits you best and change the install_name_tool call accordingly.

[Hasan Vaez]

OK man. Thank you for your attention :)

[tk421]

@SGaist Thanks for putting me on the right path. I solved my issue and just wanted to post what I learned for others to benefit from:

I had used install_name_tool to tell my PlugIns/sqldrivers/libqsqlmysql.dylib to find the libmysqlclient.dylib that was on my Mac (in my case installed using Homebrew). That worked fine until I deployed to other Macs and then they got the "Driver Not Loaded" error. I needed libqsqlmysql.dylib to link to something inside the app bundle.

It turns out that macdeployqt was copying libmysqlclient.dylib into my Frameworks directory (the output clearly shows this) but still, it didn't work!

ls -l Frameworks/*dylib
 -rw-r--r--  1   1919816 22  libcrypto.1.0.0.dylib
 -rw-r--r--  1   3723040 22  libmysqlclient.dylib
 -rw-r--r--  1    375376 22  libssl.1.0.0.dylib

The first thing I noticed about this was that the file size of libmysqlclient.dylib was smaller after the copy:

/usr/local/Cellar/mysql/5.7.18/lib/libmysqlclient.dylib -> libmysqlclient.20.dylib
/usr/local/Cellar/mysql/5.7.18/lib/libmysqlclient.20.dylib  3773144

3723040 vs 3773144 bytes? I was convinced this was the problem and wasted hours trying to figure it out. I still don't understand this, but it isn't the problem. It was a red herring.

The real problem is that libmysqlclient.dylib depends on those other 2 dylib's copied into the Frameworks directory by macdeployqt: libssl.1.0.0.dylib and libcrypto.1.0.0.dylib. I ran otool -L on each in turn, and found that libssl.1.0.0.dylib was depending on a copy of libcrypto.1.0.0.dylib outside the app bundle (again the homebrew location).

So, I had to fix the dependency of two dylib's mid-way through my build steps:

make clean
qmake -config release
make
macdeployqt MyApp.app -dmg

'make' creates MyApp.app but the Frameworks and Plugins aren't put inside it until the first execution of macdeployqt. After that, I go in and fix the dependencies:

cd MyApp.app/Contents/Frameworks
install_name_tool -change /usr/local/Cellar/openssl/1.0.2l/lib/libcrypto.1.0.0.dylib @executable_path/../Frameworks/libcrypto.1.0.0.dylib libssl.1.0.0.dylib
cd ../PlugIns/sqldrivers
install_name_tool -change /usr/local/mysql/lib/libmysqlclient.dylib @executable_path/../Frameworks/libmysqlclient.dylib libqsqlmysql.dylib
cd ../../../..
rm -rf MyApp.dmg
macdeployqt MyApp.app -dmg

After fixing the dependencies with install_name_tool, I come back to the top-level directory and delete the DMG created by that run of macdeployqt. The second time macdeployqt is executed it does not replace MyApp.app. It just complains that much of what it was going to do is done already. For example:

File exists, skip copy: "MyApp.app/Contents/PlugIns/sqldrivers/libqsqlmysql.dylib"

The second execution of macdeployqt creates the DMG with the correctly-linked dylibs.

If someone else has a similar problem, don't just copy the above steps. Use the otool -L tool on the dylibs in your app bundle to see where the dependencies are expected to be, then check to see if they are actually there. If you are deploying your app bundle to somewhere else, consider which dylib's need to be copied into your app bundle and which you can count on being on the target Mac. Finally, use install_name_tool to fix your dependencies. Hope this helps!

[Amit Talbot]

im using qt 5.9 and isolated install on mysql 5.7.20 on mac this piece of code worked like charm for me

brew install mysql-connector-c

I already had MAMP installed.... and wanted to use the mysql from mamp running on port 8889 this code helped me to do that

```

db.setHostName("localhost");
db.setConnectOptions("UNIX_SOCKET=/Applications/MAMP/tmp/mysql/mysql.sock");
db.setDatabaseName("xxxxxx");
db.setUserName("root");
db.setPassword("root");
db.setPort(8889);

[edwinxxxx]

Hi, what i have done are as pervious.but it shows that

//-bash: /Users/lucas/Qt5.9.8/5.9.8/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: cannot execute binary file"

how can i fix it? thx for your help:)

[jsulm]

@edwinxxxx said in QMYSQL driver not loaded on mac:

/Users/lucas/Qt5.9.8/5.9.8/clang_64/plugins/sqldrivers/libqsqlmysql.dylib

You can't execute a library.
What are you trying to do?

[edwinxxxx]

@jsulm coz mysql driver can't be loaded in qt creator , i followed the directions above which has been proved that it was a successful way to solve the problem.but error happens.

[jsulm]

@edwinxxxx Please tell us the exact step your executing when you get that error message

[edwinxxxx]

@jsulm

[jsulm]

@edwinxxxx The last thig you did does not make sense: you're trying to execute a lib.
The first one was not successful - you called it in a wrong way. Take a look at its output ("Usage:"), it explains how to call it.
@SGaist - you're the Mac expert, can you take a look?

[edwinxxxx]

@jsulm thanks for your tips.i have wasted the whole day to solve it😂

[SGaist]

@edwinxxxx so it's now working correctly ?

[edwinxxxx]

@sgaist
platform: macos 10.14
mysql 8.0.17
qt 5.9.8

firstly i run

//otool -L libqsqlmysql.dylib

but it shows

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/objdump: 'libqsqlmysql.dylib': No such file or directory

how can i find the path like "opt/local..." on my machine?
thanks man.

[jsulm]

@edwinxxxx said in QMYSQL driver not loaded on mac:

how can i find the path like "opt/local..." on my machine?

find / -name libqsqlmysql.dylib

[edwinxxxx]

@jsulm sorry, i still cant find any folder whose name begin with "/opt/local..."

[jsulm]

@edwinxxxx "/opt" is a system folder just under root /

[edwinxxxx]

@jsulm is that mean i cant locate the file "libmysqlclient.xx.dylib" in my pc?

[jsulm]

@edwinxxxx No, it doesn't mean that. If it is somewhere on your machine you can find it.
Where did you install it?
Did you try what I suggested?

find / -name libmysqlclient.*.dylib

[edwinxxxx]

@jsulm Yes! it shows a lot of contents, and the related information is