  A subset (~ 10%) of massive stars present strong, globally ordered (mostly
dipolar) magnetic fields. The trapping and channeling of their stellar winds in
closed magnetic loops leads to magnetically confined wind shocks (MCWS), with
pre-shock flow speeds that are some fraction of the wind terminal speed. These
shocks generate hot plasma, a source of X-rays. In the last decade, several
developments took place, notably the determination of the hot plasma properties
for a large sample of objects using XMM-Newton and Chandra, as well as fully
self-consistent MHD modelling and the identification of shock retreat effects
in weak winds. Despite a few exceptions, the combination of magnetic
confinement, shock retreat and rotation effects seems to be able to account for
X-ray emission in massive OB stars. Here we review these new observational and
theoretical aspects of this X-ray emission and envisage some perspectives for
the next generation of X-ray observatories.
