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mcallegari / qlcplus

Q Light Controller Plus (QLC+) is a free and cross-platform software to control DMX or analog lighting systems like moving heads, dimmers, scanners etc. This project is a fork of the great QLC project written by Heikki Junnila that aims to continue the QLC development and to introduce new features.
Apache License 2.0
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Fix build/linker issues with recent GCC releases and static libraries #1552

Closed cmuellner closed 2 months ago

cmuellner commented 2 months ago

Building qlcplus (upstream/master) with GCC 13.2.1 (Fedora 39) triggers build errors when using the following commands:

mkdir build
cd build
cmake ..
make

The first error is:

[...]
[ 10%] Linking CXX shared library libqlcplusengine.so
/usr/bin/ld: ../audio/src/libqlcplusaudio.a(audio.cpp.o): relocation R_X86_64_32 against symbol `_ZTV5Audio' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: failed to set dynamic section sizes: bad value
collect2: error: ld returned 1 exit status

The second error is:

[...]
[ 46%] Linking CXX shared library libqlcplusengine.so
/usr/bin/ld: ../../hotplugmonitor/src/libhotplugmonitor.a(hotplugmonitor.cpp.o): relocation R_X86_64_32 against symbol `_ZTV14HotPlugMonitor' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: failed to set dynamic section sizes: bad value
collect2: error: ld returned 1 exit status

Both errors are caused by linking a static library without position-independent code into a shared object.

This patch addresses the build errors by enabling position-independent code generation for the two static libraries.

coveralls commented 2 months ago

Coverage Status

coverage: 32.081%. remained the same when pulling e720c6eb9706071a3e5fbdd7cde61adf1e27fb3b on cmuellner:fedora-relocation into 58d4ee220b21660c1fbcded7dd9e8b8f64fdfaa7 on mcallegari:master.

mcallegari commented 2 months ago

@cmuellner thanks for this. Before merging, can you please confirm if specifying the Qt location as per wiki instructions it works correctly? https://github.com/mcallegari/qlcplus/wiki/Linux-build-(Qt5-&-cmake)#compile

Thanks

cmuellner commented 2 months ago

The PR was initially tested on Fedora 39 and linking qlcplus+changes against QT6 using the following commands:

cd build
mkdir build
cmake ..
make

I've now created an Ubuntu 23.10 VM and installed all build dependencies for a QT5 build. Then I've built qlcplus+changes using the following commands from the wiki:

cd build
mkdir build
cmake -DCMAKE_PREFIX_PATH="/usr/lib/x86_64-linux-gnu/cmake/Qt5" ..
make

Starting qlcplus worked fine.

I don't have a QT account, so I haven't tested building against the official (proprietary) Qt release.

mcallegari commented 2 months ago

Thanks :+1: