  In this paper, properties of a link $L$ in the projective space $\mathbb R
P^3$ are related to properties of its group $\pi_1(\mathbb R P^3\smallsetminus
L)$:
  $L$ is isotopic to a projective line if and only if $\pi_1(\mathbb R
P^3\smallsetminus L)=\mathbb Z$.
  $L$ is isotopic to an affine circle if and only if $\pi_1(\mathbb R
P^3\smallsetminus L)=\mathbb Z*\mathbb Z_{/2}$.
  $L$ is isotopic to a link disjoint from a projective plane if and only if
$\pi_1(\mathbb R P^3\smallsetminus L)$ contains a non-trivial element of order
two.
  A simple algorithm which finds a system of generators and relations for
$\pi_1(\mathbb R P^3\smallsetminus L)$ in terms of a link diagram of $L$ is
provided.
