From: Johannes Bauer <dfnsonfsduifb@gmx.de>
To: gdb@sourceware.org
Subject: Building gdb frontend
Date: Fri, 07 Sep 2012 10:36:00 -0000 [thread overview]
Message-ID: <5049CE37.4020005@gmx.de> (raw)
Hi list,
I'm having a strange issue with gdb. Currently I'm building a frontend
for gdb to augment its features easily. It uses Python and forks a gdb
subprocess that it communicates over stdin/stdout.
This all works nice and well, but sometimes it locks up. The frontend
always waits to see a terminated line and then the prompt "(gdb) ". So
for example, if I send "p" without arguments, usually the response will
be (calling read with a 1024 bytes buffer):
b'The history is empty.'
b'\n'
b'(gdb) '
At which I know gdb is ready to receive another command. However,
sometimes the order of these messages is messed up and reception happens
like this:
b'The history is empty.'
b'(gdb) '
b'\n'
So that my frontend waits for the prompt (because it sees "The history
is empty.(gdb) " as one line).
When I change the reading buffer to minimum size 1, the results become
even more unpredictable:
b'('
b'The history is empty.\n'
b'g'
b'd'
b'b'
b')'
b' '
i.e. "(The history is empty.\n" and "gdb) ", which also leads to a lockup.
There seems to be some kind of concurrency/buffering issue here. Is
there a way to solve this? Is there a preferred way to talk to gdb in a
"machine-readable" friendly way so I know exactly when gdb is ready to
receive commands again?
Best regards,
Johannes
next reply other threads:[~2012-09-07 10:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-07 10:36 Johannes Bauer [this message]
2012-09-07 10:46 ` Pedro Alves
2012-09-07 11:05 ` Johannes Bauer
2012-09-07 16:42 ` Andrew Burgess
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