https://svn.boost.org/trac10/ticket/9555 <p> Unit tests for 'signals' library fail to compile on Debian due to missing '#include &lt;iostream&gt;' in swap_test.cpp. </p> <p> Platform: Debian squeeze (6.0.5), target=gcc-4.6, architecture=x86, 32-bit, variant=release (debug variant compiles). Unit tests being run under bjam with 'variant=release -a -q -d2 -d+4' arguments produce the following error: </p> <blockquote> <p> "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -DBOOST_ALL_NO_LIB=1 -DBOOST_SIGNALS_NO_DEPRECATION_WARNING -DBOOST_SIGNALS_STATIC_LINK -DBOOST_TEST_NO_AUTO_LINK=1 -DNDEBUG -I"../../.." -c -o "../../../bin.v2/libs/signals/test/swap_test.test/gcc-4.6/release/link-static/swap_test.o" "swap_test.cpp" </p> </blockquote> <p> In file included from ../../../boost/config.hpp:26:0, </p> <blockquote> <p> from ../../../boost/signal.hpp:25, from swap_test.cpp:4: </p> </blockquote> <p> ../../../boost/config/user.hpp:111:0: warning: "BOOST_ALL_NO_LIB" redefined [enabled by default] &lt;command-line&gt;:0:0: note: this is the location of the previous definition swap_test.cpp: In member function 'void HelloWorld::operator()() const': swap_test.cpp:11:5: error: 'cout' is not a member of 'std' 0.000007 sec system; 0.000087 sec user ...failed gcc.compile.c++ ../../../bin.v2/libs/signals/test/swap_test.test/gcc-4.6/release/link-static/swap_test.o... ...skipped &lt;p../../../bin.v2/libs/signals/test/swap_test.test/gcc-4.6/release/link-static&gt;swap_test for lack of &lt;p../../../bin.v2/libs/signals/test/swap_test.test/gcc-4.6/release/link-static&gt;swap_test.o... SEM: &lt;s&gt;gcc-link-semaphore now used by &lt;p../../../bin.v2/libs/signals/test/swap_test.test/gcc-4.6/release/link-static&gt;swap_test ...failed updating 1 target... ...skipped 1 target... ...updated 50 targets... ERROR: building default configuration returned 1 </p> <p> Mercurial unified diff of fix: </p> <pre class="wiki">diff -r af87ea28f909 boost/libs/signals/test/swap_test.cpp --- a/boost/libs/signals/test/swap_test.cpp Thu Dec 19 23:16:23 2013 +0000 +++ b/boost/libs/signals/test/swap_test.cpp Wed Jan 08 18:20:02 2014 +0000 @@ -1,8 +1,9 @@ // https://svn.boost.org/trac/boost/ticket/5521 // claims a linker error for this. +#include &lt;iostream&gt; #include &lt;boost/signal.hpp&gt; #include &lt;boost/signals/connection.hpp&gt; struct HelloWorld { </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/9555 Trac 1.4.3