  Constraints on primordial black holes in the range $10^{-18} M_{\odot}$ to
$10^{3} M_{\odot}$ are reevaluated for a general class of extended mass
functions. Whereas previous work has assumed that PBHs are produced with one
single mass, instead there is expected to be a range of masses even in the case
of production from a single mechanism; constraints therefore change from
previous literature. Although tightly constrained in the majority of cases, it
is shown that, even under conservative assumptions, primordial black holes in
the mass range $10^{-10} M_{\odot}$ to $10^{-8} M_{\odot}$ could still
constitute the entirety of the dark matter. This stresses both the importance
for a comprehensive reevaluation of all respective constraints that have
previously been evaluated only for a monochromatic mass function, and the need
to obtain more constraints in the allowed mass range.
