QMAKE. How to figure out host platform and target platform when cross compiling QT projects - qt

Question

I compiling for QNX, ARM, My Host platform can be Win32/64 , Linux or Mac
I want to find a way to see wheat is my host platform in my PRO file (on computer I building my project)
Apparently using:
win32 {}
unix {}
macx {}
does not work because on different OSes it will always report unix, so I assume this is target platform
So what is the way to obtain current host platform to make PRO file flexible because on different platform I would like to do different things.
Thank you

Answer 1

Maybe QMAKE_HOST variable is the answer to your question?
Here's information from official Qt documentation:
QMAKE_HOST
Provides information about the host machine running qmake. For example, you can retrieve the host machine architecture from QMAKE_HOST.arch.
.arch - Host architecture
.os - Host OS
.cpu_count - Number of available cpus
.name - Host computer name
.version - Host OS version number
.version_string - Host OS version string
win32-g++:contains(QMAKE_HOST.arch, x86_64):{
message("Host is 64bit")
...
}

Answer 2

Could not get anything better then:
QMAKE_SPEC_T = $$[QMAKE_SPEC]
contains(QMAKE_SPEC_T,.*win32.*){
HOST_PLATFORM=WIN
IS_WIN = 1
}
contains(QMAKE_SPEC_T,.*macx.*){
HOST_PLATFORM=MAC
IS_MAC = 1
}
contains(QMAKE_SPEC_T,.*linux.*){
HOST_PLATFORM=LINUX
IS_LINUX = 1
}
and then anywhere to check:
!isEmpty(IS_WIN):message($${HOST_PLATFORM})
!isEmpty(IS_MAC):message($${HOST_PLATFORM})
!isEmpty(IS_LINUX):message($${HOST_PLATFORM})