@raven-worx Thanks for reply. Certainly this is a possible explanation, but that would make the actual code behind it rather old. Or the whole timeline discussion does make sense with those compilers. Also the macro states MINGW_VERSION and not GCC_VERSION.

@jsulm It seems to be fixed, but I am not sure what did it. I performed a complete sweep for viruses an malware, nothing major found. Then switched to Win10 (I go back and forth between win8 and win10), and for a while my app would not even start, with a error 0xc0000139. Did a search for that error on the web, not much help. Used depends.exe to see what DLLs were getting loaded, but found out that is a dead project, not applicable to win10. Updated a third party app I link into. Then win10 decided to do an update, which fixed the 0xc0000139 error. I cleaned up some logging events, and that improved the slow startup issue, but I cant believe that was the entire fix. Given I did so much in no certain order, in the end I cant identify what did the trick!

@VRonin Well apparently it is oO. Wasn't ware of that one, I came by it when googled the warning, but gave it not much mind. Thank you!

@dridk2 Great news! Happy coding. :)

Apologies to Diamond Platypus, I must not have had this post flagged as watch. Anyway, I did add: QMAKE_CXXFLAGS += -static-libgcc -static-libstdc++ To my .pro file I still have missing dlls: libgcc_s_dw2-1.dll libwinpthread-1.dll libstdc++-6.dll

Hi and welcome When you use the EXE outside of the compiler, it need to have some DLLS in order to run. (in the same folder as the exe) please see http://doc.qt.io/qt-5/deployment.html for short list http://www.bogotobogo.com/Qt/Qt5_Deploy_Windows_Plugins_Platforms_qwindows.php and for the best: http://www.tripleboot.org/?p=138 You can also use http://www.dependencywalker.com/ to cast some light one if you need other dlls.

@Leonardo said: Linkage is done from right to left. Maybe you're adding your static library after openssl. Put it before. Yes, you're right. Moving static library after openssl solved my issue.

Hi, Do you mean that if you build with MinGW-32 it's all working fine but not with MinGW-64 ?

For b, check whether the library has other dependencies. You might be missing one.

Hi, One fast way to build QCA with your Qt version is to build QCA using Qt Creator, you'll have everything setup correctly. If you want the features using OpenSSL you also need to install OpenSSL first. Hope it helps

@SGaist Thanks for the reply . I just noticed that i mixed dlls . I used windeployqt as you mentioned and i found all the dependencies . additionally i added these Dlls. libgcc_s_dw2-1.dll libstdc++-6.dll libwinpthread-1.dll

I have a similar issue as well. some error while compiling. although instead of undefined reference to i am getting something like deprecated function. No idea whats the problem. Thanks Scot V Development Team Fastest Web Browser