Valgrind reports:
==948== Syscall param socketcall.setsockopt(optval) points to uninitialised byte(s)
==948== at 0x1005C768E: setsockopt (in /usr/lib/system/libsystem_kernel.dylib)
==948== by 0x10199F244: pvio_socket_set_timeout (in /usr/local/lib/libmariadbclient.dylib)
==948== by 0x1019A9C1C: mthd_my_real_connect (in /usr/local/lib/libmariadbclient.dylib)
==948== by 0x1019A89D0: mysql_real_connect (in /usr/local/lib/libmariadbclient.dylib)
==948== by 0x100014174: open__OOZOOZOOZOOZOOZ85sersZlenzZOnimbleZpkgs50Zdb95connector4548O49O48454853c515153ec545556544952b575551d56a5648545349575549e48554957485253d4952Zdb95connectorZdb95mysql_u810 (db_mysql.nim:412)
==948== by 0x10061C248: _pthread_start (in /usr/lib/system/libsystem_pthread.dylib)
==948== by 0x10061840C: thread_start (in /usr/lib/system/libsystem_pthread.dylib)
==948== Address 0x7000094ffbec is on thread 3's stack
==948== in frame #1, created by pvio_socket_set_timeout (???
==948== Uninitialised value was created by a stack allocation
==948== at 0x1019AE7B0: ma_pvio_set_timeout (in /usr/local/lib/libmariadbclient.dylib)
Fixed by initializing struct timeval tm =
{0}; in pvio_socket_change_timeout (pvio_socket.c)