Blog: 2024-02-13 - Revision history

Razzi at 16:00, 13 February 2024

2024-02-13T16:00:45Z

← Older revision		Revision as of 11:00, 13 February 2024
Line 6:		Line 6:
	print(os.read(proc.stdout.fileno(), 4096))		print(os.read(proc.stdout.fileno(), 4096))
	</pre>https://stackoverflow.com/questions/39899074/communicate-multiple-times-with-a-subprocess-in-python		</pre>https://stackoverflow.com/questions/39899074/communicate-multiple-times-with-a-subprocess-in-python

			Ok it was about: buffering and flushing

			<pre>
			import os
			import subprocess

			proc = subprocess.Popen(['bc'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
			proc.stdin.write(b'100+200\n')
			proc.stdin.flush()
			print(proc.stdout.readline())
			</pre>

			flush was missing, and readline reads just a line rather than read which blocks

Razzi at 06:59, 13 February 2024

2024-02-13T06:59:29Z

← Older revision		Revision as of 01:59, 13 February 2024
Line 5:		Line 5:
	os.write(proc.stdin.fileno(), b'100+200\n')		os.write(proc.stdin.fileno(), b'100+200\n')
	print(os.read(proc.stdout.fileno(), 4096))		print(os.read(proc.stdout.fileno(), 4096))
			</pre>https://stackoverflow.com/questions/39899074/communicate-multiple-times-with-a-subprocess-in-python
	</pre>

Razzi: Created page with "How does this work but it doesn't seem to when you use the read and write methods on the io objects?

 proc = subprocess.Popen(['bc'], stdin=subprocess.PIPE, stdout=subprocess.PIPE) os.write(proc.stdin.fileno(), b'100+200\n') print(os.read(proc.stdout.fileno(), 4096))

2024-02-13T06:59:18Z

Created page with "How does this work but it doesn't seem to when you use the read and write methods on the io objects? <pre> proc = subprocess.Popen(['bc'], stdin=subprocess.PIPE, stdout=subprocess.PIPE) os.write(proc.stdin.fileno(), b'100+200\n') print(os.read(proc.stdout.fileno(), 4096)) </pre>"

New page

How does this work but it doesn't seem to when you use the read and write methods on the io objects?

<pre>
proc = subprocess.Popen(['bc'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
os.write(proc.stdin.fileno(), b'100+200\n')
print(os.read(proc.stdout.fileno(), 4096))
</pre>

Blog: 2024-02-13 - Revision history

Razzi at 16:00, 13 February 2024

Razzi at 06:59, 13 February 2024

Razzi: Created page with "How does this work but it doesn't seem to when you use the read and write methods on the io objects? proc = subprocess.Popen(['bc'], stdin=subprocess.PIPE, stdout=subprocess.PIPE) os.write(proc.stdin.fileno(), b'100+200\n') print(os.read(proc.stdout.fileno(), 4096)) "

Razzi: Created page with "How does this work but it doesn't seem to when you use the read and write methods on the io objects?
proc = subprocess.Popen(['bc'], stdin=subprocess.PIPE, stdout=subprocess.PIPE) os.write(proc.stdin.fileno(), b'100+200\n') print(os.read(proc.stdout.fileno(), 4096))
"