Re: [Mingw-cross-env-list] Undefined references when using QtNetwork

[Mark Brand]

Benjamin Kloster wrote:
> Hi everyone,

Welcome.

> I'm trying to build a Qt project depending on the QtNetwork library. The build
> system is not qmake, but CMake since it needs to integrate into a larger
> project. I followed the tutorial about setting up MXE and had some trouble
> with both the stable and the master branch (some libraries wouldn't compile
> when using just "make").

We'd like to know more about this trouble.

> I decided to try and compile my project anyway, since MXE seemed to build Qt
> and some of my own libraries successfully. However, upon compiling my Qt
> project, I get a bunch of "undefined reference" errors seemingly related to SSL
> (which I don't use yet, but will require later on). An excerpt of the error
> message:
>
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x1): undefined reference to `ASN1_INTEGER_get'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x11): undefined reference to `ASN1_STRING_data'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x21): undefined reference to `ASN1_STRING_length'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x31): undefined reference to `ASN1_STRING_to_UTF8'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x41): undefined reference to `BIO_ctrl'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x51): undefined reference to `BIO_free'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x61): undefined reference to `BIO_new'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x71): undefined reference to `BIO_new_mem_buf'
> /home/ben/tools/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.1/../../../../i686-pc-
> mingw32/lib/libQtNetwork.a(qsslsocket_openssl_symbols.o):qsslsocket_openssl_symbols.cpp:
> (.text+0x81): undefined reference to `BIO_read'
>
> and so on for a few more pages.
>
> "make openssl" in the MXE directory says there's nothing to be done for
> openssl, so it seems to be compiled properly. Same for Qt. So, how can I fix
> this?

Because we are using static linking, it's necessary to link explicitly 
to the libraries that QtNetwork depends on. You can see these in the 
.prl files (for qmake). This is taken care of automatically when you use 
qmake or pkgconfig, but perhaps not when you use cmake. What does your 
link line look like?

Mark