var-create无法创建变量对象 [英] var-create unable to create variable object

问题描述

当我调试c ++（clion）时，看不到全局字符串。我尝试检查其他类型，但效果很好。

此外，我尝试了 local 字符串，我也可以观看吗？ >

解决方案

以防万一，现在将问题跟踪为 CPP-8693 。

根本原因与libstdc ++ 双重ABI 。
std :: string 类型的全局符号以不同的方式处理，从而混淆了GDB。

在GCC 5.1版本中，libstdc ++引入了一个新的库ABI，其中包括 std :: string 和 std ::的新实现。列表。这些更改对于遵守2011 C ++标准是必要的，该标准禁止写时复制字符串，并要求列表跟踪其大小。

给出以下代码：

  std :: string global_var =嗨！ 
 static std :: string static_var = Hello; 
  

以下是相关的 nm 输出：

  0000000000602240 B _Z10global_varB5cxx11 
 0000000000602280 b _ZL10static_var 
  

可能的解决方法是禁用C ++ 11 ABI。在CMakeLists.txt中，在 set（CMAKE_CXX_STANDARD 11）行之后（如果有）添加以下行：

  add_definitions（-D_GLIBCXX_USE_CXX11_ABI = 0）
  

这将使符号名称将以不同的方式进行处理，使GDB再次感到高兴：

  0000000000602238 B global_var 
 0000000000602248 b _ZL10static_var 
  

When I debug c++ (in clion), I can't watch global strings. I tried to check other types but it worked well.

Also, I tried local string and I can watch it too?!

解决方案

Just in case, the issue is now tracked as CPP-8693.

The root cause is somehow related to libstdc++ dual ABI. Global symbols of std::string types are mangled differently, which in turn confuses GDB.

In the GCC 5.1 release libstdc++ introduced a new library ABI that includes new implementations of std::string and std::list. These changes were necessary to conform to the 2011 C++ standard which forbids Copy-On-Write strings and requires lists to keep track of their size.

Given the following code:

std::string global_var = "Hi there!";
static std::string static_var = "Hello";

Here's the related nm output:

0000000000602240 B _Z10global_varB5cxx11
0000000000602280 b _ZL10static_var

A possible workaround is to disable C++11 ABI. In CMakeLists.txt, add the following line, right after the set(CMAKE_CXX_STANDARD 11) line, if any:

add_definitions(-D_GLIBCXX_USE_CXX11_ABI=0)

This makes symbol names to be mangled differently, in a way GDB is happy again:

0000000000602238 B global_var
0000000000602248 b _ZL10static_var

这篇关于var-create无法创建变量对象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！