undefined reference when using c++11 qmake flags

Question

I have a Qt C++ application that includes a third-party library (along with its .h header file). However, when I set QMAKE_CCFLAGS += -std=c++11 and CONFIG += c++11, I get undefined reference for function calls to this third-party library.

It compiles without c++11 flags.

Is there a way to resolve this?

This is qmake specific when using c++11 flags in the qmake configuration. The DLL file is linked with qmake LIBS and is compiling without the c++11 qmake configuration flag.

Once I set:

QMAKE_CXXFLAGS += -std=c++11
CONFIG += c++11

compiling gives me unresolved symbol errors.

Overblouse

possible duplicate of What is an undefined reference/unresolved external symbol error and how do I fix it? – Adi

I believe it is not because this is happening when I link third party DLL with header files with C api functions (wrapped in extern C) using qmake, mingw, qt framework only with c++11 flags ON. Without them works just fine. – Overblouse

Answer 1

Tried the solution for this answer and it resulted in a successful compilation.

It works when I add

QMAKE_CXXFLAGS += -std=gnu++11

Qt 5.4.1 MinGW 4.9.1 32bit

Overblouse