ffcall is a C library for implementing foreign function calls in
embedded interpreters, by Bill Triggs and Bruno Haible. It allows C
functions with arbitrary argument list and return types to be called
or emulated (callbacks). It supports scalar, floating-point and
structure types. Included is also a library which implements closures,
i.e. functions with accompanying data, as first-class C functions.
ffcall supports the following CPUs: i[345]86, m68k, mips, sparc,
alpha, hppa, rs6000.

ffcall is available via anonymous FTP from
ma2s2.mathematik.uni-karlsruhe.de [129.13.115.2], in /pub/gnu.