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cmake cpack rpmbuild

I’ve been trying to analyse a core dump generated by a C++ application when it seg-faulted. I use CMake 3 to build it and create an RPM with CPack. This application is currently built in debug mode using -DCMAKE_BUILD_TYPE=Debug on the command line that invokes CMake.

The generated binaries have all their debug symbols as expected but the binaries in the RPM package do not. After some searching, I learned that rpmbuild strips binaries by default on some distributions. This makes analysing a core dump way harder than it needs to be so I found a way to turn this feature off using CPack. The trick is to set a variable in the CMakeLists.txt file:

# prevent rpmbuild from stripping binaries when in debug mode
if(CMAKE_BUILD_TYPE STREQUAL "Debug")
  set(CPACK_RPM_SPEC_INSTALL_POST "/bin/true")
endif()

Now my debug packages retain their debug info after installation so it’s possible to get a lot more information out of gdb when looking at a core dump.

This is documented in a roundabout way online, but it took me a while to figure it out so I thought I’d write it up.