Add CFLAGS to QMake project without hard-coding them in the .pro file?

environment-variables, qmake

Solution

I didn't need `$(ENV_VAR)`, but `$$(ENV_VAR)`, so I added these to my `.pro` file:

QMAKE_CXXFLAGS += $$(CXXFLAGS)
QMAKE_CFLAGS += $$(CFLAGS)
QMAKE_LFLAGS += $$(LDFLAGS)

This makes qmake respect those environment variables. Note that qmake uses `LFLAGS` instead of `LDFLAGS`.

This is still not ideal, because you can need to rerun `qmake` to change the environment variables, instead of having `make` handle them intelligently, but it's definitely better than having to edit the .pro file every time.

Problem

I'm using a distributed compiler, and I need to add `-m64` to `CFLAGS`, `CXXFLAGS` and `LDFLAGS`. Usually, my definitions in .bashrc are fine, but qmake ignores them for some reason. The standard way of doing this seems to be to edit the .pro file, but I obviously don't want to hard code the architecture. So, I can edit the .pro file, but I can't hard code anything in it. I tried setting CXXFLAGS like this: ``` QMAKE_CXXFLAGS += $(CFLAGS) ``` But it says: Makefile:17: *** Recursive variable `CXXFLAGS' references itself (eventually). Stop.

Original source