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QMake - How to add and use a variable into the .pro file

I have a qmake file generated by Qt creator. I am modifying it but I do not manage to understand how to create a variable.

For example, I want to declare the library MYPATH as I did here:

MYPATH = /lib/aaa/bbb
unix:!macx:!symbian: LIBS += -L$(MYPATH)

When I run qmake I find in the generated makefile

LIBS = ....... -L$(MYPATH) .....

But the MYPATH variable is not declared anywhere.

Does anyone know how to declare such a variable properly?

Solution

  • QMake uses its own syntax for variable references.

    • VAR = foobar => Assign value to variable when qmake is run
    • $$VAR => QMake variable's value at the time qmake is run
    • $${VAR} => QMake variable's value at the time qmake is run (identical but enclosed to separate from surrounding text)
    • $(VAR) => Contents of an Environment variable at the time Makefile (not qmake) is run
    • $$(VAR) =>Contents of an Environment variable at the time qmake (not Makefile) is run

    Try it like this

    MYPATH = /lib/aaa/bbb
unix:!macx:!symbian: LIBS += -L$${MYPATH}