How to install Qt for 32-bit compilation on an Ubuntu x86_64 machine

JonexElectronic

Hi, I have qt 5.15.2 installed for gcc64 and I want to install it to compile 32-bit programs on my x86_64 Ubuntu machine. This is the first time I'm trying to install something 32-bit on a 64-bit Linux. How do I do it? Another question, will the binary from my code's compilation be able to run on my x86_64 Ubuntu?

JonB

@JonexElectronic
I will just say that I played around trying to do this a year or so ago, and gave up, couldn't be bothered. It seemed a lot simpler to just compile for 64-bit. My recollection is you had to get so much 32-bit stuff for system libraries it was a pain.

hskoglund

You could try the old trick of installing Wine which will allow you to run 32-bit Qt.15.2 apps compiled for Windows using the MinGW compiler.
More here

jsulm

@JonexElectronic QtCompany does not provide 32bit Qt binaries anymore, you will have to build it by yourself.
A 32bit application can run on a 64bit OS.
An alternative would be to install a 32bit Ubuntu, but I'm not sure whether Ubuntu provides 32bit versions of their recent distributions.

JonexElectronic

@JonB @hskoglund @jsulm
Hi, I need to install qt-opensource-linux-x86-5.5.1. I have this file qt-opensource-linux-x86-5.5.1.run saved from many years ago, but I need to install on a lubuntu-16.04.2-desktop-amd64 and I have the next problem when I try to execute.

./qt-opensource-linux-x86-5.5.1.run
Unable to execute ./qt-opensource-linux-x86-5.5.1.run: No such file or directory

Of course, I know it is an old one bu my project need it

JonB

@JonexElectronic
But this says the file does not exist, what do you expect someone to say?

Verify (a) the file exists, (b) you are executing your command from the correct directory and lastly (c) that the file has been marked executable (chmod +x)?

JonexElectronic

@JonB yes I did all of that, I tried with an other .run file for x64 that I had and it runs but with x86 I am not able to do it

JonB

@JonexElectronic
Then I am surprised that the error message outputs No such file or directory....

What does file ./qt-opensource-linux-x86-5.5.1.run report? Also, just to humour me, ls -l ./qt-opensource-linux-x86-5.5.1.run?

JonexElectronic

@JonB

$ file ./qt-opensource-linux-x86-5.5.1.run 
./qt-opensource-linux-x86-5.5.1.run: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=79271cb8c75b1fe1aca6ebc3c32468c6e46a8a3a, not stripped

$ ls -l ./qt-opensource-linux-x86-5.5.1.run 
-rwxrwxrwx 1 lt-light lt-light 664790208 dic 29  2016 ./qt-opensource-linux-x86-5.5.1.run

JonB

@JonexElectronic
Fair enough. So this is 32-bit executable on a 64-bit x86_64 Ubuntu machine?

It may be that the error message is misleading then. There may be a dependency file missing. Now run

ldd ./qt-opensource-linux-x86-5.5.1.run

Does that show any dependent library file as "not found"?

JonexElectronic

@JonB
It is 32-bit executable on x86_64 lubuntu

$ uname -a
Linux ltlight-NF894 4.15.0-142-generic #146~16.04.1-Ubuntu SMP Tue Apr 13 09:27:15 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Here you have

$ ldd ./qt-opensource-linux-x86-5.5.1.run 
	not a dynamic executable

I think that I do not have configured something on my lubuntu or something like that

jsulm

@JonexElectronic said in How to install Qt for 32-bit compilation on an Ubuntu x86_64 machine:

qt-opensource-linux-x86-5.5.1.run

This is a script as far as I know. What I think the issue is: your Ubuntu 64bit does not provide the 32bit runtime.

JonB

@jsulm said in How to install Qt for 32-bit compilation on an Ubuntu x86_64 machine:

This is a script as far as I know.

That is what I thought, but I asked OP and earlier he reported

$ file ./qt-opensource-linux-x86-5.5.1.run 
./qt-opensource-linux-x86-5.5.1.run: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=79271cb8c75b1fe1aca6ebc3c32468c6e46a8a3a, not stripped

So how is it a script??

@JonexElectronic

Does /lib/ld-linux.so.2 exist?
If you look at the file (e.g. more ./qt-opensource-linux-x86-5.5.1.run) does it look like text/shell script or binary??

jsulm

@JonB Well, I guess I'm wrong. But it looks like it is not dinamically linked, so ldd will not work.

JonB

@jsulm said in How to install Qt for 32-bit compilation on an Ubuntu x86_64 machine:

looks like it is not dinamically linked

Interesting, since it reports:

./qt-opensource-linux-x86-5.5.1.run: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=79271cb8c75b1fe1aca6ebc3c32468c6e46a8a3a, not stripped
=> ... (GNU/Linux), dynamically linked, interpreter ...

? :)

I am working on one possible alternate theory, awaiting OP's response to

Does /lib/ld-linux.so.2 exist?

JonexElectronic

@JonB
Yes it exist

ls -l /lib/ld-linux.so.2
lrwxrwxrwx 1 root root 25 abr 21  2021 /lib/ld-linux.so.2 -> i386-linux-gnu/ld-2.23.so

Also I tried to install more things from apt

sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386

Now it gives me the next error

sudo ./qt-opensource-linux-x86-5.5.1.run 
./qt-opensource-linux-x86-5.5.1.run: error while loading shared libraries: libX11.so.6: cannot open shared object file: No such file or directory

I Installed

$ sudo apt-get install libx11-6:i386

And...

$./qt-opensource-linux-x86-5.5.1.run ./qt-opensource-linux-x86-5.5.1.run: error while loading shared libraries: libX11-xcb.so.1: cannot open shared object file: No such file or directory

Install

sudo apt-get install libx11-xcb1:i386

and..

error while loading shared libraries: libfontconfig.so.1: cannot open shared object file: No such file or directory

Install:

sudo apt-get install libfontconfig1:i386

and..

./qt-opensource-linux-x86-5.5.1.run
Could not register file downloader for https protocol: QSslSocket::supportsSsl() returns false
[9] Warning: QSslSocket: cannot call unresolved function d2i_X509
[9] Warning: QSslSocket: cannot call unresolved function d2i_X509
[9] Warning: QSslSocket: cannot call unresolved function d2i_X509
Segmentation fault (core dumped)

I Tried to solve with:

sudo apt-get install libssl1.0.0:i386
sudo apt-get install libssl-dev:i386

and..

lt-light@ltlight-NF894:~$ sudo ./Desktop/qt-opensource-linux-x86-5.5.1.run 
qt.network.ssl: QSslSocket: cannot resolve SSLv2_client_method
qt.network.ssl: QSslSocket: cannot resolve SSLv2_server_method
Segmentation fault (core dumped)

Tried

sudo apt-get update
sudo apt-get install libutil1:i386
sudo apt-get install libx11-6:i386
sudo apt-get install libx11-xcb1:i386
sudo apt-get install libxcb1:i386
sudo apt-get install libfontconfig1:i386
sudo apt-get install libfreetype6:i386
sudo apt-get install libdl2:i386
sudo apt-get install librt1:i386
sudo apt-get install libpthread0:i386
sudo apt-get install libstdc++6:i386
sudo apt-get install libm6:i386
sudo apt-get install libgcc1:i386
sudo apt-get install libc6:i386
sudo apt-get install libxau6:i386
sudo apt-get install libxdmcp6:i386
sudo apt-get install libexpat1:i386
sudo apt-get install libz1:i386
sudo apt-get install libpng12-0:i386

JonB

@JonexElectronic
OK, so you must be getting somewhere! It must indeed be some 32-bit on 64-bit issue.

For which I remind you I wrote initially

I will just say that I played around trying to do this a year or so ago, and gave up, couldn't be bothered. It seemed a lot simpler to just compile for 64-bit. My recollection is you had to get so much 32-bit stuff for system libraries it was a pain

Best of luck then, because I found it too difficult....

JonexElectronic

@JonB Thanks, I will share all process

jsulm

@JonexElectronic said in How to install Qt for 32-bit compilation on an Ubuntu x86_64 machine:

libX11.so.6

You would need to also install 32bit version of this lib. Maybe there is a way to install without opening UI? Can you try

./qt-opensource-linux-x86-5.5.1.run -h

to see what parameters it supports?

JonexElectronic

@jsulm
After many installations, I have:

./qt-opensource-linux-x86-5.5.1.run -h
Usage: ./qt-opensource-linux-x86-5.5.1.run [options] Key=Value

Options:
  -h, --help                           Displays this help.
  --version                            Displays version information.
  --framework-version                  Displays the version of the Qt Installer
                                       Framework.
  -v, --verbose                        Verbose mode. Prints out more
                                       information.
  --proxy                              Use system proxy on Windows and Linux.
                                       This option has no effect on OS X.
  --script <file>                      Execute the script given as argument.
  --checkupdates                       Check for updates and return an XML
                                       description.
  --updater                            Start application in updater mode.
  --manage-packages                    Start application in package manager
                                       mode.
  --no-force-installations             Allow deselecting components that are
                                       marked as forced.
  --show-virtual-components            Show virtual components in installer and
                                       package manager.
  --logging-rules <rules>              Enables logging according to passed
                                       rules. Comma separated logging rules have
                                       the following syntax:
                                       loggingCategory=true/false. Passing empty
                                       logging rules enables all logging
                                       categories. The following rules enable a
                                       single category:
                                       ifw.*=false,ifw.category=true The
                                       following logging categories are
                                       available:
                                       ifw.componentChecker
                                       ifw.resources
                                       ifw.translations
  --create-local-repository            Create a local repository inside the
                                       installation directory. This option has
                                       no effect on online installers.
  --addRepository <URI,...>            Add a local or remote repository to the
                                       list of user defined repositories.
  --addTempRepository <URI,...>        Add a local or remote repository to the
                                       list of temporary available repositories.
  --setTempRepository <URI,...>        Set a local or remote repository as
                                       temporary repository, it is the only one
                                       used during fetch.
                                       Note: URI must be prefixed with the
                                       protocol, i.e. file:///, https://,
                                       http:// or ftp://.
  --startserver <mode,socketname,key>  Starts the application as headless
                                       process waiting for commands to execute.
                                       Mode can be DEBUG or PRODUCTION. In DEBUG
                                       mode, the option values can be
                                       omitted.Note: The server will not
                                       shutdown on his own, you need to quit the
                                       process by hand.
  --startclient <socketname,key>       Starts the application to debug the
                                       client-server communication. If a value
                                       is omitted, the client will use a default
                                       instead. Note: The server process is not
                                       started by the client application in that
                                       case, you need to start it on your own.

Arguments:
  Key=Value                            Key Value pair to be set.

How could I Install?