[scj]

C's greatest feature is that it trivially maps onto .so files. Linking to and creating .so files isn't just cheap, it's effectively free.

Most higher level languages I've worked with seem to focus on using .so files rather than producing them.

This means the lowest common denominator for the unix ecosystem is what C can provide. Otherwise stated, unix is marching forward at the pace of C.

[samatman]

This is one of the things I like so much about Lua, LuaJIT in particular: it's designed around being just another .so file, from another clib's perspective Lua is a library for manipulating a calling stack, and the LuaJIT ffi makes it short work to adapt a header file so that structures and functions can be used from within Lua.

[pjmlp]

No wonder, given that C was created to turn UNIX from an originally Assembly written OS into a portable one, UNIX is effectively a C Machine.