For example, centos6.6 comes with gcc 4.4.7 and I installed gcc 4.9.3 myself.
When the above two standard C header files are included, will the implementation of their respective standard C libraries be connected when they are compiled with different versions of gcc respectively? Or do they share a common set of implementations?
Of course. For example, g++ from 4.7 to 4.9 has a false stl regular expression that all functions have not implemented. Later, it was realized, so of course they are different.