From: Tanaka Akira <akr@...17n.org>
Date: 2003-10-09T13:00:59+09:00
Subject: [ruby-dev:21560] exception not raised on marshaling IO

% ruby -ve 'Marshal.dump(STDIN)' 
ruby 1.8.0 (2003-10-09) [i686-linux]
% 

というように、IO を dump しても例外になりません。

なお、valgrind が

% valgrind ruby -ve 'Marshal.dump(STDIN)'
==971== Memcheck, a.k.a. Valgrind, a memory error detector for x86-linux.
==971== Copyright (C) 2002, and GNU GPL'd, by Julian Seward.
==971== Using valgrind-1.9.6, a program instrumentation system for x86-linux.
==971== Copyright (C) 2000-2002, and GNU GPL'd, by Julian Seward.
==971== Estimated CPU clock rate is 1203 MHz
==971== For more details, rerun with: -v
==971== 
ruby 1.8.0 (2003-10-09) [i686-linux]
==971== Conditional jump or move depends on uninitialised value(s)
==971==    at 0x8077884: w_object (marshal.c:661)
==971==    by 0x80778ED: dump (marshal.c:679)
==971==    by 0x805AACF: rb_ensure (eval.c:4614)
==971==    by 0x8077AB4: marshal_dump (marshal.c:748)
==971== 
==971== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
==971== malloc/free: in use at exit: 336270 bytes in 7294 blocks.
==971== malloc/free: 7563 allocs, 269 frees, 339387 bytes allocated.
==971== For a detailed leak analysis,  rerun with: --leak-check=yes
==971== For counts of detected errors, rerun with: -v

というように初期化し忘れではないかといっています。
marshal_dump が動いているのもなんですね。
-- 
[田中 哲][たなか あきら][Tanaka Akira]