1 #! [syntax]

     2 <condition> {

     3     <command or definition>

     4     ...

     5 }

     6 #! [syntax]

     7 

     8 #! [0]

     9 win32 {

    10     SOURCES += paintwidget_win.cpp

    11 }

    12 #! [0]

    13 

    14 #! [1]

    15 !win32 {

    16     SOURCES -= paintwidget_win.cpp

    17 }

    18 #! [1]

    19 

    20 unix {

    21     SOURCES += paintwidget_unix.cpp

    22 }

    23 

    24 #! [2]

    25 macx {

    26     debug {

    27         HEADERS += debugging.h

    28     }

    29 }

    30 #! [2]

    31 

    32 #! [3]

    33 macx:debug {

    34     HEADERS += debugging.h

    35 }

    36 #! [3]

    37 

    38 #! [4]

    39 win32|macx {

    40     HEADERS += debugging.h

    41 }

    42 #! [4]