Automatic Lib Init (NetworkInitializer) is not working on MinGW

[asari-fd]

I'm writing a network client using Poco and MinGW.
It seems that I have to call Poco::Net::initializeNetwork() before calling any network-related functions, otherwise I get an exception like "DNS error: EAI: 10093", which means WSANOTINITIALISED (according to http://support.microsoft.com/kb/819124/) -- is it intended?

I think I'd be happy if I can always omit initializeNetwork() calls. Thanks.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.1 LTS
Release:    14.04
Codename:   trusty

$ dpkg -l | grep mingw32
ii  mingw32                           4.2.1.dfsg-2ubuntu1                      amd64        Minimalist GNU win32 (cross) compiler
ii  mingw32-binutils                  2.20-0.2ubuntu1                          amd64        Minimalist GNU win32 (cross) binutils
ii  mingw32-runtime                   3.15.2-0ubuntu1                          all          Minimalist GNU win32 (cross) runtime

$ i586-mingw32msvc-gcc --version
i586-mingw32msvc-gcc (GCC) 4.2.1-sjlj (mingw32-2)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ cat VERSION 
1.6.0 (2014-12-22)

[aleks-f]

Network initialization is a Windows-specific thing and we have it done for the supported Visual Studio compiler. We don't officially support mingw, but we encourage contributions; so, you'll either have to come up with a solution or wait for one of the mingw contributors to help.

[asari-fd]

I understand. Thanks for your comment.

[Speakus]

The issue is inside Poco/Net/Net.h file. I update this to fix issue: http://pastebin.com/3fWrnw0q

[aleks-f]

fixed

[OldWolf2]

With MinGW-w64 7.2.0 and poco-1.8.1-release, this problem recurs but only if POCO_STATIC=1 and we static link to Poco. (It worked correctly for a DLL-based POCO build). I work around this by explicitly calling Poco::Net::initializeNetwork() in my code.

[aleks-f]

@OldWolf2 See if this helps and let us know, we may add it:

diff --git a/Net/include/Poco/Net/Net.h b/Net/include/Poco/Net/Net.h
index 0d7bd35..f5bd912 100644
--- a/Net/include/Poco/Net/Net.h
+++ b/Net/include/Poco/Net/Net.h
@@ -92,7 +92,9 @@ void Net_API uninitializeNetwork();
 
 extern "C" const struct Net_API NetworkInitializer pocoNetworkInitializer;
 
-#if defined(Net_EXPORTS)
+#if defined(__GNUC__)
+       #define POCO_NET_FORCE_SYMBOL(x) void *__ ## x ## _fp =(void*)&x;
+#elif defined(Net_EXPORTS)
        #if defined(_WIN64) || defined(_WIN32_WCE)
                #define POCO_NET_FORCE_SYMBOL(s) __pragma(comment (linker, "/export:"#s))
        #elif defined(_WIN32)

[aleks-f]

obviously
&& !defined(__GNUC__)
should be removed as well for the above to work

[jackorobot]

@aleks-f The following patch I have tested and verified the following patch (building on your proposal) works with mingw gcc on windows. Will propose the change in a merge request if this is still something you would want to have implemented here.

diff --git a/Net/include/Poco/Net/Net.h b/Net/include/Poco/Net/Net.h
index 2e9735ab2..785de0ef0 100644
--- a/Net/include/Poco/Net/Net.h
+++ b/Net/include/Poco/Net/Net.h
@@ -93,11 +93,13 @@ std::string htmlize(const std::string& str);
 // Automate network initialization (only relevant on Windows).
 //

-#if defined(POCO_OS_FAMILY_WINDOWS) && !defined(POCO_NO_AUTOMATIC_LIB_INIT) && !defined(__GNUC__)
+#if defined(POCO_OS_FAMILY_WINDOWS) && !defined(POCO_NO_AUTOMATIC_LIB_INIT)

 extern "C" const struct Net_API NetworkInitializer pocoNetworkInitializer;

-#if defined(Net_EXPORTS)
+#if defined(__GNUC__)
+       #define POCO_NET_FORCE_SYMBOL(x) static void *__ ## x ## _fp = (void*)&x;
+#elif defined(Net_EXPORTS)
        #if defined(_WIN64) || (defined(_WIN32_WCE) && !defined(x86))
                #define POCO_NET_FORCE_SYMBOL(s) __pragma(comment (linker, "/export:"#s))
        #elif defined(_WIN32)

[aleks-f]

@jackorobot I don't mind it, you can send a pull. but it would be good to also have a CI job for that