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Date: | Thu, 28 Jan 2010 11:21:19 +0000 |
From: | Andrew West <andrewwest AT gmail DOT com> |
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To: | cygwin AT cygwin DOT com |
Subject: | dlclose not calling destructors of static variables. |
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--------------030505030402020304050403 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit I seem to be having a problem with dlclose not calling the destructors of statically declared variables. I've attached a simple test case which I compile as follows; testlib.cpp g++ -g -shared testlib.cpp -o testlib testrunner.cpp g++ -g testrunner.cpp -o testrunner -ldl When running testrunner, I get the following output; Running test_runner testlib:: start TestClass::TestClass() Running test_lib testlib:: stop Segmentation fault (core dumped) Compiling and running the same code on linux gives me the expected result of; Running test_runner testlib:: start TestClass::TestClass() Running test_lib TestClass::~TestClass() testlib:: stop Digging through with gdb, __EntryPoint() registers the destructor of TestClass with atexit but dlclose doesn't call the atexit for the dll it's unloading leaving the TestClass destructor in the atexit list when the program exits even thou testlib.dll has been unloaded, hence the segfault. I'm afraid I'm don't really know much about how the internals of cygwin/library loading and unloading works. Is this a simply a case of dll_list::detach needing to call __cxa_finalize with a reference to the dll being unloaded? Andy --------------030505030402020304050403 Content-Type: text/plain; name="testrunner.cpp" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="testrunner.cpp" #include <iostream> #include <dlfcn.h> typedef int ( *ENTRYFUNC )(); int main( int argc, char** argv ) { std::cout << "Running test_runner" << std::endl; void* dll = 0; dll = dlopen( "testlib.dll", RTLD_LAZY ); if ( !dll ) { std::cout << "Could not open library: " << dlerror() << "." << std::endl; return 0; } ENTRYFUNC dllFunc = ( ENTRYFUNC ) dlsym( dll, "__EntryPoint" ); if ( !dllFunc ) { std::cout << "Could not find library entry point" << std::endl; dlclose( dll ); return 0; } dllFunc(); if ( 0 != dlclose( dll ) ) { std::cout << "Could not close library" << std::endl; return 0; } return 1; } --------------030505030402020304050403 Content-Type: text/plain; name="testlib.cpp" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="testlib.cpp" #include <iostream> #include <cstdlib> struct TestClass { TestClass() { std::cout << "TestClass::TestClass()" << std::endl; } ~TestClass() { std::cout << "TestClass::~TestClass()" << std::endl; } }; static void start() __attribute__ ((constructor)); static void stop() __attribute__ ((destructor)); extern "C" void __EntryPoint() { static TestClass t1; std::cout << "Running test_lib" << std::endl; } void start(void) { std::cout << "testlib:: start" << std::endl; } void stop(void) { std::cout << "testlib:: stop" << std::endl; } --------------030505030402020304050403 Content-Type: text/plain; charset=us-ascii -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple --------------030505030402020304050403--
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