Josh,
> My real question is: how can I pass floating-point arguments to
> native library functions obtained by using dlopen/dlsym?
Currently you can't (at least not reliably and portably) since there
is no way to tell the Jolt compiler how to coerce the 64-bit Float
contents into a 32- or 64-bit float or double nor how to store the
resulting value in registers or stack as an argument. Adding types
to Jolt is high on my to-do list and should be done within the next
few weeks. (As well as native floats and non-integer parameters
it'll add some degree of static type safety when dealing with known
interfaces, such as those described in /usr/include.)
The work-around that I've been using is to create a thin wrapper in
Pepsi around the library of interest, then send messages to the
wrapper from Jolt. To extract the float/double from a Float argument
you can, e.g:
Float print
{
double d;
memcpy(&d, self, sizeof(d));
printf("%g", d);
}
(the memcpy is required, to avoid violating alignment restrictions)
and to return a Float:
Float sin
[
self := self copy.
{
double d;
memcpy(&d, self, sizeof(d));
d = sin(d);
memcpy(self, &d, sizeof(d));
}
]
Of course this doesn't help you pass floats or doubles through
'...' (to the printf functions, for example) but it might help fill a
gap until we have types.
Cheers,
Ian
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