Author: Dave Gomboc
Date: 16:41:29 10/25/03
Go up one level in this thread
On October 25, 2003 at 09:49:58, Tord Romstad wrote:
>I use the gcc (version 3.2) included with the Cygwin tools to compile the
>Windows version
>of my engine. The last month or so, the Windows version has had a mysterious
>problem:
>When compiled with the -fbranch-prediction flag, it consistently crashed at move
>109 or
>110 when running in UCI mode. The problem never occured in Winboard mode, it
>never
>occured in either UCI or Winboard mode in Linux or MacOS X, and it disappeared
>when
>I compiled without -fbranch-prediction (but this makes the engine much slower).
>
>After spending a few hours debugging, I found that the crash occurs in the
>following
>innocent-looking function:
>
>void uci_wait_for_command() {
> char command[10000];
>
> fgets(command, 10000, stdin);
> uci_handle_command(command); }
>
>It is the call to fgets which causes the crash. The reason why the problem
>occures at
>move 109 or 110 is probably because the string sent by the GUI with the
>"position"
>command gets very long (though nowhere near 10000 characters) after so many
>moves.
>
>Increasing the size of the command[] array did not have any effect. However,
>when I
>changed the command[] array to a global variable, the crashes suddenly
>disappeared.
>
>Is this likely to be a bug in gcc, or could it be caused by a bug somewhere else
>in
>my source code?
>
>Tord
I'd suspect a bug in your code, but of course it's hard to say for sure.
Try bumping up your stack size.
Try valgrind (http://developer.kde.org/~sewardj/).
Dave
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