Pop a double from the stack
int SLang_pop_double (double *dptr, int *iptr, int *conv)
The SLang_pop_double function pops a double precision number
from the stack and returns it via dptr. If the number was
derived from an integer, *conv will be set to 1 upon
return, otherwise, *conv will be set to 0. This
function returns 0 upon success, otherwise it returns -1 and sets
SLang_Error accordingly.
If one does not care whether or not *dptr was derived from
an integer, iptr and conv may be passed as NULL
pointers.
SLang_pop_integer, SLang_push_double