编译iOS应用时，使用升压能见度链接器警告 [英] Visibility linker warnings when compiling iOS app that uses Boost

问题描述

我的iOS应用使用的库而这又取决于升压。虽然改造了的3rdParty构建系统，我遇到了连接器这样的警示

My iOS app uses a library which in turn depends on Boost. While revamping the 3rdparty build system, I encountered linker warnings such as this

ld: warning: direct access in ___cxx_global_var_init to global weak symbol
std::__1::basic_ofstream<char, std::__1::char_traits<char> >::~basic_ofstream()
means the weak symbol cannot be overridden at runtime.
This was likely caused by different translation units being compiled with different visibility settings.

这

ld: warning: direct access in __GLOBAL__I_a to global weak symbol
boost::exception_ptr::~exception_ptr()
means the weak symbol cannot be overridden at runtime.
This was likely caused by different translation units being compiled with different visibility settings.

我看到有对SO对此警告不少其他的问题。我也跟着他们的建议并确保在所有的可见性设置版本是相同的（ = -fvisibility隐藏和 -fvisibility - 内联隐藏）。一个完整的重建后，我还是得到了警告。

I saw that there are quite a few other questions on SO regarding this warning. I followed their advice and made sure that the visibility settings in all builds are the same (-fvisibility=hidden and -fvisibility-inlines-hidden). After a full rebuild I still got the warnings.

环境：

X code 4.6.0

• 的iOS SDK 6.1


• 采用了时下流行的的修改克隆galbraithjosephs-boostoniphone 构建脚本大厦升压


• 加速版本1.54.0


• 与 -std = C ++ 11 -stdlib = ++的libc 建筑

• Xcode 4.6.0
• iOS SDK 6.1
• Building Boost using a modified clone of the popular galbraithjosephs-boostoniphone build script
• Boost version 1.54.0
• Building with -std=c++11 -stdlib=libc++

推荐答案

的问题是，所用的加速构建脚本铛++ 作为编译器，但其他图书馆和我的自己的iOS应用中使用铛（其他图书馆和我的应用程序在哪里建立与铛）。

The problem was that the Boost build script used clang++ as the compiler, but the other library and my own iOS app used clang (the other library and my app are Xcode projects where builds are made with clang).

该警告消失后，我重建加强与铛。

The warnings disappeared after I rebuilt Boost with clang.

可悲的是，我完全不知道为什么，这有助于。据我所知，有铛++编译切换到编译C ++模式下，开启/关闭特定设置。但它肯定不能意味着使用铛++ 覆盖可见性设置是的明确的在命令行上指定的？评论或额外的答案解释的行为是受欢迎的。

The sad thing is that I don't know exactly why this helped. I am aware that compiling with clang++ switches the compiler into C++ mode, turning on/off certain settings. But it certainly can't mean that using clang++ overrides visibility settings that are explicitly specified on the command line?! Comments or additional answers explaining the behaviour are welcome.

这篇关于编译iOS应用时，使用升压能见度链接器警告的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！