c - How can I see why libstc++ is needed -

i'm writing c application using opengl. code c99 compliant , i'm not using c++ @ all. program links opengl libs , sdl2.

running ldd get:

linux-vdso.so.1 (0x00007ffd456e0000) libsdl2-2.0.so.0 => /lib64/libsdl2-2.0.so.0 (0x00007fccdb862000) libglew.so.1.13 => /lib64/libglew.so.1.13 (0x00007fccdb5d7000) libglu.so.1 => /lib64/libglu.so.1 (0x00007fccdb368000) libgl.so.1 => /lib64/libgl.so.1 (0x00007fccdb0d9000) libm.so.6 => /lib64/libm.so.6 (0x00007fccdadcf000) libc.so.6 => /lib64/libc.so.6 (0x00007fccdaa0c000) libdl.so.2 => /lib64/libdl.so.2 (0x00007fccda808000) libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fccda5ec000) librt.so.1 => /lib64/librt.so.1 (0x00007fccda3e3000) libx11.so.6 => /lib64/libx11.so.6 (0x00007fccda0a3000) libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007fccd9d1c000) libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fccd9b04000) libglx.so.0 => /lib64/libglx.so.0 (0x00007fccd98d4000) libgldispatch.so.0 => /lib64/libgldispatch.so.0 (0x00007fccd95eb000) /lib64/ld-linux-x86-64.so.2 (0x000055a76893d000) libxcb.so.1 => /lib64/libxcb.so.1 (0x00007fccd93c8000) libxext.so.6 => /lib64/libxext.so.6 (0x00007fccd91b6000) libxau.so.6 => /lib64/libxau.so.6 (0x00007fccd8fb1000) 

as can see links against libstdc++, guess lib need it. how can check call requesting lib or more information issue? thanks.

run application ld_debug=all <cmd-line>, e.g.:

ld_debug=all kwin --version |& grep "needed by" 

outputs:

... 17448:  file=libc.so.6 [0];  needed kwin [0] 17448:  file=libxcb-image.so.0 [0];  needed /lib64/libkwin4_effect_builtins.so.1 [0] ...