Compiling: undefined reference "clock_gettime and memcpy" for Qt project - qt

Question

I try to compile Qt project with CentOS.
This question describe what I have done in detail and
I want to do with another glibc libraries /users/my/lib64/ (I can't update /lib64/) by referring to this.
This is the compile out put:
g++ ./main.o ./moc_widget.o ./widget.o \
-o ./test -Wl,--rpath=/users/my/lib64 \
-Wl,--rpath=/users/my/Qt/5.9.1/gcc_64/lib \
-Wl,--dynamic-linker=/users/my/lib64/libc.so.6 \
-Wl,--dynamic-linker=/users/my/lib64/libz.so.1 \
-L/users/my/Qt/5.9.1/gcc_64/lib -lQt5Widgets \
-lQt5Gui -lQt5Core -lGL -lpthread -lglib-2.0 -lrt -lX11 \
-I/users/my/test/2 \
-I/users/my/Qt/5.9.1/gcc_64/include \
-I/users/my/Qt/5.9.1/gcc_64/include/QtWidgets \
-I/users/my/Qt/5.9.1/gcc_64/include/QtCore \
-I/users/my/Qt/5.9.1/gcc_64/include/QtGui
.pro file :
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = test
TEMPLATE = app
DEFINES += QT_DEPRECATED_WARNINGS
CONFIG += qt
SOURCES += \
main.cpp \
widget.cpp
HEADERS += \
widget.h
FORMS += \
widget.ui
gcc version : 6.1.0
But the error:
/users/my/Qt/5.9.1/gcc_64/lib/libQt5Core.so: undefined reference to `clock_gettime#GLIBC_2.17'
/users/my/Qt/5.9.1/gcc_64/lib/libQt5Widgets.so: undefined reference to `memcpy#GLIBC_2.14'
collect2 ld returned exit 1 status
How to solve it ?

Answer 1

g++ ./main.o ./moc_widget.o ./widget.o \
-o ./test -Wl,--rpath=/users/my/lib64 \
-Wl,--rpath=/users/my/Qt/5.9.1/gcc_64/lib \
-Wl,--dynamic-linker=/users/my/lib64/libc.so.6 \
-Wl,--dynamic-linker=/users/my/lib64/libz.so.1 \
-L/users/my/Qt/5.9.1/gcc_64/lib -lQt5Widgets \
-lQt5Gui -lQt5Core -lGL -lpthread -lglib-2.0 -lrt -lX11 \
-I...
This command line is completely bogus (you didn't understand previous answer): there can only be one dynamic linker, and it should be /users/my/lib64/ld-linux-x86-64.so.2, and not libz.so.1. By using multiple --dynamic-linker=... flags, you are simply replacing previous (incorrect) setting with a new (also incorrect) one.
It's also bogus because specifying -I... flags on the link line without any sources is pointless.
If this command succeeded, you'd end up with an executable that would simply crash immediately, because libz.so.1 is not a dynamic linker.
Now, your link fails because you are performing the link on the wrong system. You need to link on the original system (the one where you successfully linked your binary earlier, and the one which has GLIBC 2.17 or later). And then move the linked executable to your target system.
On the original system, your link command should look something like this:
g++ main.o moc_widget.o widget.o -o test \
-Wl,-rpath=/users/my/lib64 \
-Wl,--dynamic-linker=/users/my/lib64/ld-linux-x86-64.so.2 \
-L...
The two lines I indented above should be the only change from your original successful link command.