[mythtv-users] Frontend crash when LCD enabled

Neil Bird neil at fnxweb.com
Wed Jun 28 11:04:25 UTC 2006

   After I updated my box from FC3 to FC5, I found that the frontend was 
crashing trying to talk to lcdproc (0.4, same version as was working under 
FC3, just recompiled).

   I did a debug build opf myth to try to track it down, but the problem 
goes away with (a) 'mythfrontend -v all', (b) debug builds of the libraries, 
(c) running under gdb in most instances.

   I pretty much had to resort to inserting debug into non-debug builds :-/

   Anyway, although my C++ is up to par, my Qt knowledge isn't, so I was 
wondering if anyone out there had any ideas.  It actually looks like it 
might be a glitch in Qt.  Below's a dump I got when I did manage to catch 
the crash in gdb.

   The debug output I added pointed to the same line:  under writeBlock() 

(gdb) bt
#0  0x00000000 in ?? ()
#1  0x013913e5 in QTextStream::writeBlock (this=0xbf824fe0, p=0x7b737ce 
"HELLO\n", len=6) at tools/qtextstream.cpp:1084
#2  0x01391676 in QTextStream::operator<< (this=0xbf824fe0, s=0x7b737ce 
"HELLO\n") at tools/qtextstream.cpp:2136
#3  0x079b3e0b in LCD::connectToHost () from /usr/lib/libmyth-0.19.so.0
#4  0x079b4515 in LCD::SetupLCD () from /usr/lib/libmyth-0.19.so.0
#5  0x0806a568 in ?? ()
#6  0x00126724 in __libc_start_main () from /lib/libc.so.6
#7  0x08062c51 in ?? ()

(gdb) list
1079            if (!d->encoder)
1080                d->encoder = mapper->makeEncoder();
1081            QString s = QString::fromLatin1(p, len);
1082            int l = len;
1083            QCString block = d->encoder->fromUnicode(s, l);
1084            dev->writeBlock(block, l);
1085        }
1086    #endif
1087        else {
1088            for ( uint i = 0; i < len; i++ )

(gdb) print *dev
warning: can't find linker symbol for virtual table for `QIODevice' value
$2 = {_vptr.QIODevice = 0x2e0031, ioIndex = 3014704, ioMode = 3014704, ioSt 
= 3276849}
(gdb) print block
$3 = {<QMemArray<char>> = {<QGArray> = {_vptr.QGArray = 0x15f80a8, shd = 
0x99d1fa0}, <No data fields>}, <No data fields>}

[neil at fnx ~]# rm -f .signature
[neil at fnx ~]# ls -l .signature
ls: .signature: No such file or directory
[neil at fnx ~]# exit

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