Handle an expected child-process failure.
Python: Catch CalledProcessError when check=True reports a nonzero exit status.
import subprocess, sys
try:
subprocess.run([sys.executable, "-c", "raise SystemExit(3)"], check=True)
except subprocess.CalledProcessError as error:
print(error.returncode)Expected output EXAMPLE
3
Details
Save as snippet.py and run python3 snippet.py. Uses the Python standard library. Catch CalledProcessError when check=True reports a nonzero exit status.
Tested on Ubuntu 24.04.5 LTS · · Python 3.12.3 · python3 3.12.3-0ubuntu2.1
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged) / C.UTF-8
- Interpreter invocation
python3 -c <published code>- Container image ID
sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd- Code SHA-256
db867cc0cdaa4454f7a1361e8a5f4fd057641ae2f58c87e98842c470ae154628- Dependencies
- python3 3.12.3-0ubuntu2.1
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
# No input files required.
Observed standard output
3
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.