Devel::CallChecker makes some new features of the Perl 5.14.0 C API available to
XS modules running on older versions of Perl. The features are centred around
the function cv_set_call_checker, which allows XS code to attach a magical
annotation to a Perl subroutine, resulting in resolvable calls to that
subroutine being mutated at compile time by arbitrary C code. This module makes
cv_set_call_checker and several supporting functions available. (It is possible
to achieve the effect of cv_set_call_checker from XS code on much earlier Perl
versions, but it is painful to achieve without the centralised facility.)

Devel::CallCheckerprovides the implementation of the functions at runtime (on
Perls where they are not provided by the core). It also, at compile time,
supplies the C header file and link library which provide access to the
functions. In normal use, "callchecker0_h" and "callchecker_linkable" should be
called at build time (not authoring time) for the module that wishes to use the
C functions.