OpenBSD: stdout and stderr problem

[marianielias]

Hi guys!
I'm trying to bring Wurlitzer to OpenBSD and the following problem arises:

Currently c_stdout_p and c_stderr_p is defined here:
https://github.com/minrk/wurlitzer/blob/1.0.1/wurlitzer.py#L32

Getting the symbol "stdout" for default and "__stderrp" for Mac OS X.

OpenBSD has neither:
https://github.com/openbsd/src/blob/master/include/stdio.h#L198

I tried to work it out myself but I'm not to savvy in C/Python interfacing.
I understand that __sF is an array with pointers to stdout (__sF[1]) and stderr (__sF[2]).
So we should get the __sF array and then cast __sF[n] to the equivalent of &__sF[n] ?

Again, maybe there is a more direct approach.

Cheers.
Elias.

[minrk]

Looking at openbsd, I can't seem to get an easy way to access what we need without a compilation step, since we need two pieces of info:

1. location of __sF (easy, same as others), and
2. sizeof(FILE) to locate __sF[1] etc.

If we had easy access to sizeof(FILE), I think we'd be okay, but I can't figure out how to determine without compiling something. And if we are going to compile anyway, it can be pretty simple with cffi:

        _ffi = cffi.FFI()
        _ffi.cdef("const size_t c_stdout_p();")
        _ffi.cdef("const size_t c_stderr_p();")
        _lib = _ffi.verify(
            '\n'.join(
                [
                    "#include <stdio.h>",
                    "const size_t c_stdout_p() { return (size_t) (void*) stdout; }",
                    "const size_t c_stderr_p() { return (size_t) (void*) stderr; }",
                ]
            )
        )
        # if we always require cffi, this step is unnecessary
        c_stdout_p = ctypes.c_void_p(_lib.c_stdout_p())
        c_stderr_p = ctypes.c_void_p(_lib.c_stderr_p()) 

That ought to work just about everywhere, BUT requires a compiler