Fix for PowerPC: handle libffi's integer return type promotion #405
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When the return type of a function is an integer type narrower than the system register size,
libffi
promotes it toffi_arg
.On big-endian systems, this causes problems with calls to functions that return small integers (
char
,short
, etc.), sincelibffi
writes the return value to anffi_arg
-sized slot, and ctypes attempts to read the value from the same address using a pointer to the return type rather than a pointer toffi_arg
.This pull request adds a compensating offset to the return value address passed to ctypes on big-endian systems for both regular function calls (d00922e) and callbacks (d6c200a), and a new test for callbacks that return small integers (9f3cb97).