'How can I link to a custom library when building MySQL Server from source?

I installed MySQL server using a standard source distribution (mysql-server-8.0) according to this url: https://dev.mysql.com/doc/refman/8.0/en/installing-source-distribution.html. For some purpose, I added some code to MySQL source code in mysql-server-8.0/sql/mysqld.cc, and the code I added used a custom .so library in /usr/lib.

I want to link to this library when building MySQL source code, so when I built MySQL, I used following commands:

cmake .. -DWITH_BOOST=/home/ubuntu/mysql-server-8.0/boost \
         -DCMAKE_C_FLAGS="-lmy_lib_name -L/usr/lib" \
         -DCMAKE_CXX_FLAGS="-lmy_lib_name -L/usr/lib" \
         -DCMAKE_C_LINK_FLAGS="-lmy_lib_name -L/usr/lib" \
         -DCMAKE_CXX_LINK_FLAGS="-lmy_lib_name -L/usr/lib" \
         -DCONFIG_CLIENT_LIBS="-lmy_lib_name -L/usr/lib" \
         -DCONFIG_LIBS_PRIVATE="-lmy_lib_name -L/usr/lib" \
         -DCMAKE_EXE_LINKER_FLAGS="-lmy_lib_name -L/usr/lib" \
         -DCMAKE_MODULE_LINKER_FLAGS="-lmy_lib_name -L/usr/lib" \
         -DCMAKE_SHARED_LINKER_FLAGS="-lmy_lib_name -L/usr/lib" \
make

Although I tried to add flag when compiling and linking, it failed to complete building, reporting that error: undefined reference to 'symbols in my library' . Is there any way to make it work? Thanks!

mysqllinuxubuntucmake


Solution 1:[1]

Thanks for your comments! I found that I didn't correctly use C in .cc source file. It should be noticed that in .cc file C headers should be used like:

extern "C" {
  #include "mylib.h"
}

So the linking procedure worked fine. The compiler can't identify the function signature because of my misuse of the library headers in .cc file.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 hsyhhh

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