[issue25789] py launcher stderr is not piped to subprocess.Popen.stderr

Wolfgang Maier added the comment: > The error() function in PC/launcher.c should call exit(rc) instead of > ExitProcess(rc). This allows the CRT to terminate properly and flush the > stderr FILE stream. Interesting. Why do you need to flush stderr? I would have expected it to be unbuffered

[issue25789] py launcher stderr is not piped to subprocess.Popen.stderr

Changes by Vinay Sajip : -- nosy: +vinay.sajip ___ Python tracker ___ ___

[issue25789] py launcher stderr is not piped to subprocess.Popen.stderr

Eryk Sun added the comment: Patch 2 additionally modifies run_child to call exit() instead of ExitProcess. For example: >>> import os, subprocess >>> os.environ['PYLAUNCH_DEBUG'] = '1' >>> p = subprocess.Popen(r'py -3 -c ""', stderr=subprocess.PIPE, stdout=subprocess.PIPE) >>>

[issue25789] py launcher stderr is not piped to subprocess.Popen.stderr

Steve Dower added the comment: ExitProcess is a system API and exit is the C runtime API. The C runtime is doing the buffering, so the system doesn't know about it and can't flush if you terminate through that API. The exit function should, or we could explicitly flush the buffer after

[issue25789] py launcher stderr is not piped to subprocess.Popen.stderr

New submission from Wolfgang Maier: from the console: > py -3.7 or any other not installed Python version gives: Requested Python version (3.7) not installed However, when the launcher is executed from python via subprocess.Popen: >>>import subprocess >>>p=subprocess.Popen(['py', '-3.7'],

[issue25789] py launcher stderr is not piped to subprocess.Popen.stderr

Eryk Sun added the comment: The error() function in PC/launcher.c should call exit(rc) instead of ExitProcess(rc). This allows the CRT to terminate properly and flush the stderr FILE stream. With this change it works as expected: >>> import subprocess >>> p =