Linking with a debug/release lib with qmake/Qt Creator

c++ qt qmake
Rob picture Rob · Jul 15, 2009 · Viewed 23.3k times · Source

I am using Qt Creator and have a Qt GUI project that depends on a C++ static library project. I want to link the release version of the GUI app with the release build of the .lib and the debug release of the GUI app with the debug .lib. I have found out how to add additional libraries to the project by including a line like the following in my .pro file:

LIBS += -L./libfolder -lmylib.lib

But I cannot see how I can use a different -L command for release and debug builds.

Is there support in qmake to do this?

Answer

Marc Mutz - mmutz picture Marc Mutz - mmutz · Jul 15, 2009

The normal

debug:LIBS += ...
else:LIBS += ...

solution breaks when users naively use CONFIG += debug or CONFIG += release to switch between debug and release builds (and they do; no-one remembers to say CONFIG -= release release_and_debug before CONFIG += debug :).

This is the canonical way to scope on debug:

CONFIG( debug, debug|release ) {
    # debug
    QMAKE_LIBDIR += "path/to/debug/lib"
} else {
    # release
    QMAKE_LIBDIR += "path/to/release/lib"
}

Cf. the qmake docs.

EDIT 2013-11-17: Don't use -Lfoo in LIBS. The canonical way is to add the paths (without the -L) to QMAKE_LIBDIR.

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