what are the build-in libraries of gnu libc

[haperkelu]

When I　start progrmming in c, I can invoke some system calls( such as read ,fork,exevp) without including any libraries.
Is there the possiblity that the gcc complier automatically search the default library?

[kyku]

The default library is linked automatically with every C/C++ program, unless you explicitly tell the compiler not to do so. You can use ldd exe_file to find out what a libraries were linked with the executable. Hope this helps.