LTTng » LTTng-UST

The Userspace libary will fail to build when crosscompiling, this is easily repruducable with Buildroot for example.

As far as I can tell, the transitive dependency to liblttng-ust-tracepoint.so.0 when referencing liblttng-ust.so is lost,
I suppose it would not appear if the host or sysroot contains an installed liblttng-ust-tracepoint.so.0.

Error Message is following:

[ 70%] Linking CXX executable tester
/usr/bin/cmake -E cmake_link_script CMakeFiles/tester.dir/link.txt --verbose=1
/tmp/build/host/bin/x86_64-buildroot-linux-gnu-g++ -g -O2 -rdynamic CMakeFiles/tester.dir/tester.cpp.o -o tester -Wl,-rpath,/tmp/a/doc/examples/cmake-multiple-shared-libraries/build:/tmp/a/liblttng-ust/.libs libaligner-lib.so libtester-lib.so libtracepoint-provider.so /tmp/a/liblttng-ust/.libs/liblttng-ust.so -ldl
/tmp/build/host/lib/gcc/x86_64-buildroot-linux-gnu/7.2.0/../../../../x86_64-buildroot-linux-gnu/bin/ld: warning: liblttng-ust-tracepoint.so.0, needed by /tmp/a/liblttng-ust/.libs/liblttng-ust.so, not found (try using -rpath or -rpath-link)
/tmp/a/liblttng-ust/.libs/liblttng-ust.so: undefined reference to `exit_tracepoint'
/tmp/a/liblttng-ust/.libs/liblttng-ust.so: undefined reference to `__tracepoint_probe_unregister_queue_release'
/tmp/a/liblttng-ust/.libs/liblttng-ust.so: undefined reference to `__tracepoint_probe_register_queue_release'
/tmp/a/liblttng-ust/.libs/liblttng-ust.so: undefined reference to `__tracepoint_probe_prune_release_queue'
/tmp/a/liblttng-ust/.libs/liblttng-ust.so: undefined reference to `init_tracepoint'
collect2: error: ld returned 1 exit status

This issue is atleast occuring in 2.9.0, 2.9.1 and 2.10.0