man gcc гласит
...
FILES
     file.c             C source file
     file.h             C header (preprocessor) file
     file.i             preprocessed C source file
     file.C             C++ source file
     file.cc            C++ source file
     file.cxx           C++ source file
     file.m             Objective-C source file
     file.s             assembly language file
     file.o             object file
     a.out              link edited output
     TMPDIR/cc*         temporary files
     LIBDIR/cpp         preprocessor
     LIBDIR/cc1         compiler for C
     LIBDIR/cc1plus     compiler for C++
     LIBDIR/collect     linker front end needed on some machines
     LIBDIR/libgcc.a    GCC subroutine library
     /lib/crt[01n].o    start-up routine
     LIBDIR/ccrt0       additional start-up routine for C++
     /lib/libc.a        standard C library, see
     intro(3)
     /usr/include       standard directory for #include files
     LIBDIR/include     standard gcc directory for #include files
     LIBDIR/g++-include additional g++ directory for #include

     LIBDIR is usually /usr/local/lib/machine/version.
     TMPDIR comes from the environment variable  TMPDIR  (default
     /usr/tmp if available, else /tmp).
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