How can I detect in the .pro file if I am compiling on a 32 bit or a 64 bit platform?

You can use QMAKE_HOST.arch for this. The QMAKE_HOST variable expresses host information about the machine running qmake and QMAKE_HOST.arch allows you to determine the target architecture. You can use it as follows:

win32-g++:contains(QMAKE_HOST.arch, x86_64):{
do something
}

3 comments

May 3, 2011

ludde

Ant Farmer

If I understand things correctly, QMAKE_HOST.arch will tell you if you are compiling on a 32 or 64 bit platform, which is not necessarily the same as the platform you are compiling for, right?

May 4, 2011

sigrid

Lab Rat

That’s correct. You can use QMAKE_TARGET.arch to decide the platform you are building for. We have added the following FAQ [developer.qt.nokia.com] for this now:

March 18, 2013

hrodstein

Lab Rat

Using Qt 4.8.4, this works for me on Windows but not on Macintosh. On Macintosh
message($$QMAKE_TARGET.arch)
prints nothing in the Qt creator Compile Output pane while on Windows it prints x86_64.

I am not in a position to test in Qt 5.

I have reported this as a bug: https://bugreports.qt-project.org/browse/QTBUG-30263

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How can I detect in the .pro file if I am compiling on a 32 bit or a 64 bit platform?

3 comments

May 3, 2011

May 4, 2011

March 18, 2013

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