ld: library not found for -lmysqlclient_r (when trying to build mysql driver on mac)

SGaist

Then replace -lmysqlclient_r with -lmysqlclient.

The _r means re-entrant but AFAIK, the latest versions of the client libraries should be re-entrant anyway.

LeeH

I just tried that, and no luck gave the same error for '-lmysqlclient' :(

SGaist

You still need to give the linker the path where to find the librairies.

Add

LIBS += -L/path/to/MySQL_libs/

to your .pro file.

LeeH

This post is deleted!

LeeH

Hi sorry to be a pain, still not worked yet... If I've understood you I tried:

adding path to lib 'LIBS += -L/usr/local/mysql/lib' to my mysql.pro:

TARGET = qsqlmysql

LIBS += -L/usr/local/mysql/lib     <---

HEADERS += $$PWD/qsql_mysql_p.h
SOURCES += $$PWD/qsql_mysql.cpp $$PWD/main.cpp

QMAKE_USE += mysql

OTHER_FILES += mysql.json

PLUGIN_CLASS_NAME = QMYSQLDriverPlugin
include(../qsqldriverbase.pri)

then run qmake cmd with '-lmysqlclient'

qmake "INCLUDEPATH+=/usr/local/mysql/include" "LIBS+=-L/usr/local/lib -lmysqlclient" mysql.pro

make

SGaist

What exact error do you get this time ?

LeeH

Now that you mentioned the error, I can see that it's still refering to '-lmysqlclient_r' even though I ran '-lmysqlclient'. I wonder what thats about? Here it is:

Last login: Sat May 27 23:01:02 on console
Leons-Mac:~ ldigital$ cd Qt/5.8/Src/qtbase/src/plugins/sqldrivers/mysql
Leons-Mac:mysql ldigital$ qmake "INCLUDEPATH+=/usr/local/mysql/include" "LIBS+=-L/usr/local/lib -lmysqlclient" mysql.pro
Leons-Mac:mysql ldigital$ make
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f  Makefile.Release all
rm -f libqsqlmysql.dylib
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -headerpad_max_install_names -stdlib=libc++ -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk -mmacosx-version-min=10.9  -Wl,-rpath,@loader_path/../../lib -single_module -dynamiclib -o libqsqlmysql.dylib .obj/release/qsql_mysql.o .obj/release/main.o .obj/release/moc_qsql_mysql_p.o  -F/Users/ldigital/Qt/5.8/clang_64/lib -L/usr/local/lib -lmysqlclient -L/usr/local/mysql/lib -framework QtSql -framework QtCore -framework DiskArbitration -framework IOKit -L/opt/local/lib/mysql55/mysql -lmysqlclient_r -lz  
ld: warning: directory not found for option '-L/opt/local/lib/mysql55/mysql'
ld: library not found for -lmysqlclient_r
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [../../../../plugins/sqldrivers/libqsqlmysql.dylib] Error 1
make: *** [release-all] Error 2

SGaist

Edit /qtbase/src/sql/configure.json and change the library name.

LeeH

ok here is the libraries section for mysql in configure.json:

 "mysql": {
        "label": "MySQL",
        "test": "unix/mysql",
        "sources": [
            { "type": "mysqlConfig", "query": "--libs_r" },
            { "type": "mysqlConfig", "query": "--libs" },
            { "libs": "-lmysqlclient_r", "condition": "!config.win32" },
            { "libs": "-llibmysql", "condition": "config.win32" },
            { "libs": "-lmysqlclient", "condition": "!config.win32" }
        ]
    },

I removed (temporarily) the '-libmysqlclient_r' line seeing as '-libmysqlclient' is already there, and tried again but still gives the same error for -lmysqlclient_r

SGaist

Don't remove it, updated it, see the condition part.

You should also cleanup your build folder and try to build from scratch.

LeeH

ok do you mean:

 { "libs": "-lmysqlclient_r", "condition": "-lmysqlclient" },   ?

because I have no idea whats going on here tbh

SGaist

I meant: just remove the _r. The condition basically states that this line apply all configurations that are not win32.

Note that I missed the one further down. So in fact, removing it was a correct solution, sorry for the confusion.

LeeH

That's ok. Is there anything else I can try? this is really stressing me out, and I am still searching the web for other solutions... one is homebrew but I don't know if I should or not. What do you think?

SGaist

Personally I usually use macports which is a homebrew equivalent to get my dependencies on macOS but both are fine.

LeeH

Thanks for that. I shall leave you in peace for a while as I explore them and see how things turn out, and thanks so much for your help so far. I really appreciate it.

LeeH

YEEAAH!

After another 2 days of battling, I FINALLY got it working. I had totally given up on the conventional method of doing this for mac, as it was getting me no where. I still cannot for the life of me understand why Qt didn't load this very popular driver in the release and why building this driver on mac is so difficult when I had previously got it working on windows the conventional way much easier (thanks to @SGaist and others).

Anyway Homebrew worked by installing Qt and MySql together: (this takes a very long time)

brew install qt5 --with-mysql

after that installed Qt creator:

brew cask install qt-creator

then configured MySql as normal through terminal as it seems you can't get sysprefpane this way.

Hopefully this can help others, and a big thanks to @SGaist for taking the time!