Calling a C function that returns a function pointer panics #501

PureGo Version

v0.10.2, and main as of today

Operating System

• Windows
• macOS
• Linux
• FreeBSD
• NetBSD
• Android
• iOS

Go Version (go version)

go1.26.5 linux/amd64

What steps will reproduce the problem?

Declare a C function that returns a function pointer, so the Go side has a func return type:

var fn func() func(a, b int32) int32
purego.RegisterLibFunc(&fn, lib, "return_func_ptr")
add := fn()

Registering it is fine, its the call that goes, and it goes for every signature I tried.

What is the expected result?

fn() hands back a callable func(int32, int32) int32.

What happens instead?

panic: reflect.MakeFunc: value of type *func(int32, int32) int32 is not assignable to type func(int32, int32) int32

Anything else you feel useful to add?

The RegisterFunc type table has func <=> C function in it, but that only seems to hold in the argument direction. Every other case in that return switch leaves the result as the declared type - the reflect.Func case swaps in a *func, registers into that, and hands the pointer back to MakeFunc, which wont take it.

Been that way since #49 in 2022 as far as I can tell. Fix and a test are in #500.