Problem:
When compiling your C++ application, you see one or more of the following or similar error messages (complete error message log example shown below)
dso_dlfcn.c:(.text+0x17): undefined reference to `dlopen' /usr/bin/ld: dso_dlfcn.c:(.text+0x2a): undefined reference to `dlsym' /usr/bin/ld: dso_dlfcn.c:(.text+0x35): undefined reference to `dlclose' dso_dlfcn.c:(.text+0x1b7): undefined reference to `dlsym' /usr/bin/ld: dso_dlfcn.c:(.text+0x282): undefined reference to `dlerror' dso_dlfcn.c:(.text+0x2f5): undefined reference to `dlopen' /usr/bin/ld: dso_dlfcn.c:(.text+0x369): undefined reference to `dlclose' /usr/bin/ld: dso_dlfcn.c:(.text+0x3a5): undefined reference to `dlerror' dso_dlfcn.c:(.text+0x466): undefined reference to `dladdr' /usr/bin/ld: dso_dlfcn.c:(.text+0x4d7): undefined reference to `dlerror'
Solution:
You need to link the dl (dynamic linker) library to your executable. When running gcc manually, use the -ldl option, for example:
gcc -o myexe main.cpp -ldl
When using CMake, use
add_executable(myexe main.cpp) target_link_libraries(myexe dl)
Full error log example:
/usr/bin/ld: /home/uli/.conan/data/openssl/1.1.1k/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib/libcrypto.a(dso_dlfcn.o): in function `dlfcn_globallookup': dso_dlfcn.c:(.text+0x17): undefined reference to `dlopen' /usr/bin/ld: dso_dlfcn.c:(.text+0x2a): undefined reference to `dlsym' /usr/bin/ld: dso_dlfcn.c:(.text+0x35): undefined reference to `dlclose' /usr/bin/ld: /home/uli/.conan/data/openssl/1.1.1k/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib/libcrypto.a(dso_dlfcn.o): in function `dlfcn_bind_func': dso_dlfcn.c:(.text+0x1b7): undefined reference to `dlsym' /usr/bin/ld: dso_dlfcn.c:(.text+0x282): undefined reference to `dlerror' /usr/bin/ld: /home/uli/.conan/data/openssl/1.1.1k/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib/libcrypto.a(dso_dlfcn.o): in function `dlfcn_load': dso_dlfcn.c:(.text+0x2f5): undefined reference to `dlopen' /usr/bin/ld: dso_dlfcn.c:(.text+0x369): undefined reference to `dlclose' /usr/bin/ld: dso_dlfcn.c:(.text+0x3a5): undefined reference to `dlerror' /usr/bin/ld: /home/uli/.conan/data/openssl/1.1.1k/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib/libcrypto.a(dso_dlfcn.o): in function `dlfcn_pathbyaddr': dso_dlfcn.c:(.text+0x466): undefined reference to `dladdr' /usr/bin/ld: dso_dlfcn.c:(.text+0x4d7): undefined reference to `dlerror' /usr/bin/ld: /home/uli/.conan/data/openssl/1.1.1k/_/_/package/6af9cc7cb931c5ad942174fd7838eb655717c709/lib/libcrypto.a(dso_dlfcn.o): in function `dlfcn_unload': dso_dlfcn.c:(.text+0x6b8): undefined reference to `dlclose'