Qt的编程中包含了插件模式，使得程序的扩展性非常好，但插件的动态加载的检查也比较严格，这次编译数据库驱动插件就碰到了不少问题。实际上，可以在系统的 环境变量中设置QT_DEBUG_PLUGINS＝1 ，即在终端中执行 export QT_DEBUG_PLUGINS=1
再执行程序加载插件时，再系统控制台上会输出许多加载插件时的调试信息，可以清楚的看到系统尝试加载了哪些插件，哪些是成功的，哪些没有成功，原因是什么都写的比较清楚。因此，如果自己编译的插件库无法加载，可以用这个方式检查以下到底是哪里的问题。
//-------------------------------------
在没有添加QT_DEBUG_PLUGINS＝1时，运行程序：
Open: "/dev/ttyO1"
Open: "/dev/ttyO4"
+++++++++++++++++++++++++++++++++++++++++++++++++++.
++++++++++++++++++++++++Create Command Thread.....
+++++++++++++++++++++++++++++++++++++++++++++++++++.
defaultServiceProvider::requestService(): no service found for - "org.qt-project
.qt.audiosource"
Input Devices Can Used :
()
===========
Default Input Devices :
""
-------------------
Encoder:
//-------------------------------------
添加QT_DEBUG_PLUGINS＝1(即在即在终端中执行 export QT_DEBUG_PLUGINS=1)
//-------------------------------------
Open: "/dev/ttyO1"
Open: "/dev/ttyO3"
Open: "/dev/ttyO4"
QFactoryLoader::QFactoryLoader() checking directory path "/workspace/mediaservic
e" ...
QFactoryLoader::QFactoryLoader() looking at "/workspace/mediaservice/libqtmedia_
audioengine.so"
+++++++++++++++++++++++++++++++++++++++++++++++++++.
++++++++++++++++++++++++Create Command Thread.....
+++++++++++++++++++++++++++++++++++++++++++++++++++.
QElfParser: ‘/workspace/mediaservice/libqtmedia_audioengine.so‘ is an invalid EL
F object (string table seems to be at a100)
"‘/workspace/mediaservice/libqtmedia_audioengine.so‘ is an invalid ELF object (s
tring table seems to be at a100)"
not a plugin
defaultServiceProvider::requestService(): no service found for - "org.qt-project
.qt.audiosource"
Input Devices Can Used :
()
===========
Default Input Devices :
""
-------------------
可以看到 提示的更详细，libqtmedia_audioengine.so 有问题，再排查吧
原文：https://www.cnblogs.com/totogo/p/14737669.html