On 6/27/2014 1:52 PM, Yaakov Selkowitz wrote:
On 2014-06-27 12:11, Ken Brown wrote:
On 6/25/2014 10:17 PM, Ken Brown wrote:
This is a followup to
https://cygwin.com/ml/cygwin/2014-06/msg00324.html, from which I
extracted the following test case:
$ cat gfile-test.c
#include <stdio.h>
#include <gio/gio.h>
void
gfile_add_watch (const char *file)
{
GFile *gfile = g_file_new_for_path (file);
GFileMonitor *monitor;
GFileMonitorFlags gflags = G_FILE_MONITOR_NONE;
monitor = g_file_monitor (gfile, gflags, NULL, NULL);
if (! monitor)
printf ("Can't watch file %s\n", file);
else
printf ("Watching file %s\n", file);
}
int
main ()
{
const char *file = "gfile-test.c";
gfile_add_watch (file);
}
$ gcc -g -O0 -o gfile-test $(pkg-config --cflags gio-2.0) gfile-test.c
$(pkg-config --libs gio-2.0)
In the 64-bit case, this behaves as expected:
$ ./gfile-test.exe
Watching file gfile-test.c
In the 32-bit case, however, it crashes. Running it under gdb shows
that the call to g_file_monitor leads to a SEGV, but I can't tell
exactly where; when I try to single step through the Glib code, I
eventually hit an assertion violation in gdb. strace shows lots of
exceptions, but I can't make much sense out of it otherwise.
I rebuilt glib and gamin without optimization so that I could step
through the code in gdb. But stepping through the code turned out to be
unnecessary, because the bug was gone after the rebuilds. I don't know
if optimization was really the issue or whether just rebuilding with the
latest tools is what fixed it.
My builds can be obtained from
http://sanibeltranquility.com/cygwin/
if anyone else wants to try to reproduce this without rebuilding the
packages themselves.
Yaakov, could you take a look?
Sure. Are you narrow this down to only one of glib or gamin?
The culprit is gamin, and optimization *is* relevant. What's strange,
though, is that when I rebuild it with optimization, my test case hangs
instead of crashing. Summary:
- With gamin-0.1.10-14 (and its subpackages), my test case crashes. The
outward symptom is that there's no output, but running the test case
under gdb shows the SEGV.
- If I rebuild gamin without optimization, I don't see any bug. More
precisely, I build it using your gamin.cygport with the following line
added:
CFLAGS+=" -O0 -g3"
- If I rebuild gamin with optimization (i.e., just using your
gamin.cygport with no changes), my test case hangs.
Ken
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