wurlitzer for capturing C-level stdout/stderr

cap.py

import ctypes
import io
import os

from wurlitzer import STDOUT, pipes, sys_pipes

import ophyd


def test():
    sig = ophyd.EpicsSignal("simple:A")
    sig.wait_for_connection()
    print("value", sig.get())
    sig.destroy()


out = io.StringIO()
libc = ctypes.CDLL(None)

with sys_pipes():
    with pipes(stdout=out, stderr=STDOUT):
        test()
        print("foobar")
        print(12)
        libc.puts(b"this comes from C")
        os.system("echo and this is from echo")

print('Got combined stdout/stderr: "{0}"'.format(out.getvalue()))

output.txt

# start two IOCs
$ python -m caproto.ioc_examples.simple --list-pvs &
$ python -m caproto.ioc_examples.simple --list-pvs &

$ python cap.py
Got combined stdout/stderr: "CA.Client.Exception...............................................
    Warning: "Identical process variable names on multiple servers"
    Context: "Channel: "simple:A", Connecting to: 192.168.2.110:53494, Ignored: pc98125.home:5064"
    Source File: ../cac.cpp line 1320
    Current Time: Wed May 10 2023 16:14:44.793322496
..................................................................
value 1
foobar
12
this comes from C
and this is from echo
"