[Interest] Is there a command line call to qmake to test the bit width?

[Thiago Macieira]

On Wednesday 04 March 2015 18:39:55 Scott Aron Bloom wrote:
> No.  Maybe Im not explaining myself correctly.  Since this was purely a
> question on qmake, or if there was anyway to look at a Qt install an see
> what bit width it was built against.
> 
> However here are all the gory details.
> 
> On a single system, I have 2 versions of the SAME Qt installed, 64 bit and
> 32 bit, both installed correctly.

Good, I have that too. Actually, 6 builds of the same Qt.

> Visual Studio has two compilers, one for 64 and one for 32.  That said, when
> I used to release our tool for linux 32, we had a similar issue..
> 
> The developers setup build script, requires the "cl" to be pointing to the
> correct cl, ie, that you have run vsvars before you run cmake (which then
> has the dependency on qmake)

Right.

> If I am trying to build the 64 bit system, but my shell is pointing to the
> 32 bit compiler, but the 64 bit Qt system, it will most likely compile just
> fine, but it will not link correctly.

Right.

> Im trying to put the logic into my CMake system, to query the version of
> qmake to determine, if the user has selected the appropriate Visual Studio
> and Qt version.

$ qmake -o /dev/null /dev/stdin <<<'message($$QT_ARCH)'
Project MESSAGE: x86_64
$ qmake -qt5-i386 -o /dev/null /dev/stdin <<<'message($$QT_ARCH)'
Project MESSAGE: i386
$ qmake -qt5-arm -o /dev/null /dev/stdin <<<'message($$QT_ARCH)'
Project MESSAGE: arm
$ qmake -qt5-mips -o /dev/null /dev/stdin <<<'message($$QT_ARCH)'
Project MESSAGE: mips

Since you're in a less-than-capable shell and OS, you'll need to create a file 
to pass to qmake instead of /dev/stdin.

Note that this does not catch different ABIs in the same OS. If there's 
interest for that, we can start recording the ABI in a qmake variable for 
Qt 5.5. For me, they'd be:

	x86_64-little_endian-lp64
	i386-little_endian-ilp32
	arm-little_endian-ilp32-eabi
	mips-little_endian-ilp32-o32-hardfloat

Note: on Windows, 64-bit says "x86_64-little_endian-llp64" (note the extra l). 
See http://doc.qt.io/qt-5/qsysinfo.html#buildAbi
-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center