Qt5 Interface

From Lazarus wiki
Jump to: navigation, search
Qt logo 2013.svg

This article applies to Qt5 widgetset only.

See also: Multiplatform Programming Guide


This interface is based on Qt 5 (Qt 5.6.2 is tested). For documentation, fixes and download, go to Qt Project (Installers at download 5.6.2). Lazarus with Qt5 interface (qt5-lcl) can be used on Windows 32/64, Linux x32/x64/arm, MacOSX x64(Cocoa). Qt5 widgetset is available from lazarus trunk 1.7 rev. 53806 and will be available in lazarus 1.8 stable release. There's no support for 32bit Qt5 binary versions from Digia, so if you need 32bit Qt5 on linux you must build complete Qt5 on your own, including libQt5Pas.

Quick start guide for Linux

Bindings sources are located in lcl/interfaces/qt5/cbindings , to build it just follow README.txt.

Step-by-step guide for macOS 64bit

The following steps have been tested with macOS 10.13.6 (High Sierra), Xcode command line tools 10.0.0 (no Xcode required), Lazarus 1.8.4 and Qt 5.6.2.

After installing Qt 5.6.2 (see above), open up a terminal window and run these commands (paths may vary):

cd $LazarusDir/lcl/interfaces/qt5/cbindings

If qmake fails with the following error:

xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

it does not mean that you have to install Xcode. See Qt without Xcode for a workaround and try running qmake again. (The Xcode dependency seems to be fixed in Qt 5.9.4 or maybe earlier.)

Proceed the build process with the following commands:

make install

It may be helpful to add symlinks to the Qt5Pas.framework and other *.framework files (so no modifications to the path are required):

cd /Library/Frameworks/
sudo ln -s $QtDir/5.6/clang_64/lib/*.framework .

Remember that Qt5 is 64bit, so in Lazarus under Tools - Options - Environment, you need to change Compiler Executable from /usr/local/bin/ppc386 to /usr/local/bin/ppcx64 . With ppc386, you would later get the following errors when compiling your Lazarus projects:

Error: linker: Undefined symbols for architecture i386:
Error: linker: "_QAbstractButton_click", referenced from:
ld: symbol(s) not found for architecture i386

Finally, create a new Lazarus project (or open an existing one), open Project - Project options - Compiler options - Additions and overrides, set LCLWidgetType:=qt5 . You should now be able to compile your project with the Qt5 widget set.

See [1] for an example project.

Other Interfaces

Platform specific Tips

Interfaces Development Articles