1#! [syntax]
2<condition> {
3    <command or definition>
4    ...
5}
6#! [syntax]
7
8#! [0]
9win32 {
10    SOURCES += paintwidget_win.cpp
11}
12#! [0]
13
14#! [1]
15!win32 {
16    SOURCES -= paintwidget_win.cpp
17}
18#! [1]
19
20unix {
21    SOURCES += paintwidget_unix.cpp
22}
23
24#! [2]
25macx {
26    debug {
27        HEADERS += debugging.h
28    }
29}
30#! [2]
31
32#! [3]
33macx:debug {
34    HEADERS += debugging.h
35}
36#! [3]
37
38#! [4]
39win32|macx {
40    HEADERS += debugging.h
41}
42#! [4]
43