Unix gcc compilation error: Symbol referencing errors. No output written to test

Yes when compiling to. O files. When linking these. O files, an error is reported.

Inet_ton testserver. O (symbol belongs to implicit dependency/usr/lib/libnsl. so.1)
Inet_ntoa fun. O (symbol belongs to implicit dependency/usr/lib/libnsl. so.1)

The reason is that it does not know the functions inet_ton and inet_ntoa in it, and it needs to add the corresponding static library. This library has already prompted you, symbol belongs to implicit dependency/usr/lib/libnsl. so.1, so you must add-lnsl to the Command during compilation.

OK.