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Re: printf + pthreads+gdb+mintty = hang?

On 08/05/2013 2:36 PM, Christopher Faylor wrote:
On Tue, May 07, 2013 at 04:22:23PM -0400, Ryan Johnson wrote:
Hi all,

Running the attached STC inside gdb hangs (zero CPU util, have to kill
gdb from Task Manager, killing a.exe doesn't cut it).

Compile line used: g++ -Wall -g -mthreads -DBUG bug.cpp

I currently have the following package versions:
cygwin-1.7.18(0.263/5/3) 2013-04-19

The problem seems to be related to threads calling fprintf inside gdb,
it runs fine from the command line, or with printf instead; both fprintf
and printf sometimes trigger "warning: SuspendThread failed. (winerr 6)"
(not sure if that matters).

Known issue? Easy workaround? New bug?
Known, long-standing issue.  I put a workaround in the latest snapshot.
Hmm. The STC still hangs about 25% of the time (down from ~100%), so things are improved but not fixed.

Also, when I hit an assertion failure in my code, gdb successfully breaks in at my breakpoint on abort()---which used to hang---but then hangs as soon as I say "up 2" to see the actual source of the assertion failure. Unfortunately, I haven't been able to distill that one down to a reasonable STC: just arranging for a threaded toy app to call abort from multiple threads simultaneously doesn't seem to tickle the bug.


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