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Qt5.3+OpenCV2.4.9 on MacOS "Undefined symbols for architecture x86_64:" Issue

This issue is answered in this post


and explained by sandy.martel

I quoted here

Qt binary distribution compile with -stdlib=libstdc++ to be compatible with 10.6, Xcode 5 on 10.9 will select -stdlib=libc++ by default (for OS X 10.7 and better only).

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Issues Solution


1. 问题描述

  • 用QTCreater建立了一个纯C++的项目,但是在F5调试时,竟然提示ptrace不允许的操作,修改工程配置为Debug也不管用,经过网上搜索,原来还需要修改一下系统ptrace的配置。

2. 解决办法

  • 临时性的解决方法
    • $ sudo echo 0 > /proc/sys/kernel/yama/ptrace_scope
  • 这样不过重启电脑之后就又恢复成原来的样子了,一劳永逸的方法:
    • $ sudo vi /etc/sysctl.d/10-ptrace.conf
    • $ kernel.yama.ptrace_scope = 0
    • 重启电脑就好了,
  • 据说在Ubuntu 11.04之后都会出现这种问题,貌似是为了安全

3. ptrace

  • 那么ptrace是个什么东西,可能是Linux下边调试时用到的?目前还不知道,以后要做一下研究
Issues Solution

Android's back button and Qt

In the case when you want to handle back button in Android by Qt you have to override QWidget:keyPressEvent() method. This method receives all key event for its widget. 39 more words