The Perl function calls for dealing with sockets have the same names as the corresponding system calls in C, but their arguments tend to differ for two reasons: first, Perl filehandles work differently than C file descriptors. Second, Perl already knows the length of its strings, so you don't need to pass that information.
One of the major problems with old socket code in Perl was that it used
hard-coded values for some of the constants, which severely hurt
portability. If you ever see code that does anything like explicitly
setting $AF_INET = 2, you know you're in for big trouble: An immeasurably superior approach is
to use the Socket module, which more reliably grants access to various constants and
functions you'll need.