You can also define them in build file (xmake.lua) target("test") set_kind("binary") add_files("src/*.c", "src/*.cpp") add_cflags("

You can also define them in build file (xmake.lua) target("test") set_kind("binary") add_files("src/*.c", "src/*.cpp") add_cflags("-fPIC", "-Dxxx") add_cxxflags("-fPIC", "-Dxxx") The command line arguments just give you a quick and easy way to modify cflags.