FreeBSD support

[ilius]

Hi

Here I will post results of my tests on FreeBSD.

Initially I was getting these errors on compilation:

# github.com/mappu/miqt/qt
In file included from gen_qabstractanimation.cpp:11:
cgo-gcc-export-header-prolog:58:69: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:59:70: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:89:74: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:98:61: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:99:64: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:106:97: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:110:80: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:114:85: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:163:73: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:165:75: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:194:76: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:234:63: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:235:64: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:331:74: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:332:74: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:333:74: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:338:80: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:367:92: error: unknown type name '_Bool'
cgo-gcc-export-header-prolog:370:90: error: unknown type name '_Bool'
fatal error: too many errors emitted, stopping now [-ferror-limit=]

After @mappu's help on ilius/ayandict#6, and setting this environment variable

export CGO_CXXFLAGS='-D_Bool=bool'

Compilation was successful on all my tests.

Let's start with the examples in this repo:

• helloworld: works

• helloworld6: works

• marshalling: go test -> ok

• mdoutliner: compiles but does not run:

   QObject: Cannot create children for a parent that is in a different thread.
   (Parent is QApplication(0x39515ac2b100), parent's thread is QThread(0x39515ac2b110), current thread is QThread(0x39515d80e010)
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   failed to authenticate magic 1
   failed to load driver: iris
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QApplication::exec: Must be called from the main thread
  

  I tried compiling with export CGO_CXXFLAGS='--std=c++13' (because c++13 command is available) and got the same unknown type name '_Bool' error

• uidesigner: the window shows up, but I still get these errors:

   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject: Cannot create children for a parent that is in a different thread.
   (Parent is QApplication(0x10c02c2b100), parent's thread is QThread(0x10c02c2b110), current thread is QThread(0x10c05818000)
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
   failed to authenticate magic 1
   failed to load driver: iris
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
   QObject::setParent: Cannot set parent, new parent is in a different thread
  

My C++

$ c++ --version
FreeBSD clang version 18.1.5 (https://github.com/llvm/llvm-project.git llvmorg-18.1.5-0-g617a15a9eac9)
Target: x86_64-unknown-freebsd14.1
Thread model: posix
InstalledDir: /usr/bin

$ c++13 --version
c++13 (FreeBSD Ports Collection) 13.2.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[ilius]

Here is another program https://gist.github.com/ilius/e438497a2c46eb712464ee505affcd41
It compiles with same CGO_CXXFLAGS='-D_Bool=bool' but window does not show up and get this:

QObject: Cannot create children for a parent that is in a different thread.
(Parent is QApplication(0x1279f6c2b270), parent's thread is QThread(0x1279f6c2b280), current thread is QThread(0x1279f9809000)
QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
QBasicTimer::start: QBasicTimer can only be used with threads started with QThread
QObject::setParent: Cannot set parent, new parent is in a different thread
QApplication::exec: Must be called from the main thread

It was fixed after changing (nil) calls to the 2() methods that do not take parent:
https://gist.github.com/ilius/e438497a2c46eb712464ee505affcd41/revisions

[mappu]

I think the threading issues are caused because Qt expects UI calls to be made from the "main thread", but the Go runtime balances OS threads automatically, and it made a decision to migrate your main function into another thread. This decision is somewhat random based on CPU usage and availability, so, I can't reproduce it today on x86_64 Linux, but it might reproduce under higher load.

The fix involves calling runtime.LockOSThread().

• If you add this call in your main function, does it solve the problem?

Probably this could be added directly in MIQT when calling qt.NewQApplication.

[ilius]

Wow. Indeed, calling runtime.LockOSThread() before NewQApplication seems to make it always work.