-lboost_system找不到库 [英] library not found for -lboost_system

问题描述

我使用macports安装了boost。文件似乎在/ opt / local / include / boost /

我的makefile不再工作，我收到以下错误

 未定义符号：
boost :: system :: generic_category（），引用自：
 __static_initialization_and_destruction_0（int，int） .o 
 __static_initialization_and_destruction_0（int，int）in client.o 
boost :: system :: system_category（），引用自：
 boost :: asio :: error :: get_system_category ）in client.o 
 boost :: system :: error_code :: error_code（）in client.o 
 __static_initialization_and_destruction_0（int，int）in client.o 
 ld：symbol（s）not发现
 collect2：ld返回1退出状态
 make：*** [client]错误1 
  

在学校解决方案是使用-lboost_system作为g ++的参数，但现在我已经把项目回家到我的mac，这不工作。我认为这主要是因为在学校，boost文件在usr / local / lib（或类似的地方）。

当我添加-lboost_system参数我得到以下消息

  g ++ -I / opt / local / include -lboost_system -o client client.o Packet.o 
 ld：未找到-lboost_system的库库
 collect2：ld返回1退出状态
 make：*** [client]错误1 
  

我已经尝试了一些变体使用-L和-l，但我似乎找不到一个组合工作。在学校我也不必使用-L。我在这里读了一些其他类似的问题的帖子，但他们通过添加-l标志，它不为我工作固定它。

帮助！感谢！

解决方案

您缺少一个 -L / opt / local / lib 。您应该能够在Makefile中设置 LDFLAGS ：

  LDFLAGS = -L / opt / local / lib 
  

这假设Boost库在 / opt / local / lib 当然。

如果你不使用通常的 CXXFLAGS 和 LDFLAGS 变量，然后直接添加 -L / opt / local / lib 在您的最终规则中：

  client：client.o Packet.o 
 g ++ -L / opt / local / lib -o client client.o Packet.o -lboost_system 
  

-I 只告诉编译器头文件在哪里，链接器需要库，你使用 -L 。

I installed boost using macports. The files appear to be in /opt/local/include/boost/

My makefile is no longer working and I get the following error

Undefined symbols:
"boost::system::generic_category()", referenced from:
  __static_initialization_and_destruction_0(int, int)in client.o
  __static_initialization_and_destruction_0(int, int)in client.o
"boost::system::system_category()", referenced from:
  boost::asio::error::get_system_category()    in client.o
  boost::system::error_code::error_code()in client.o
  __static_initialization_and_destruction_0(int, int)in client.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [client] Error 1

at school the solution was to use -lboost_system as an argument to g++, but now that I've taken the project home to my mac, this does not work. I think this is mostly due to the fact that at school the boost files were at usr/local/lib (or somewhere similar).

When I add the -lboost_system argument i get the following message

g++ -I/opt/local/include -lboost_system -o client client.o Packet.o
ld: library not found for -lboost_system
collect2: ld returned 1 exit status
make: *** [client] Error 1

I've tried a few variations using -L and -l, but I can't seem to find a combo that works. At school I also do not have to use -L. I've read a few other posts here about similar problems, but they fixed it by adding -l flags which arent working for me.

Help! thanks!

解决方案

You're missing a -L/opt/local/lib. You should be able to set the LDFLAGS in your Makefile:

LDFLAGS=-L/opt/local/lib

This assumes that the Boost libraries are in /opt/local/lib of course.

If you're not using the usual CXXFLAGS and LDFLAGS variables in your Makefile, then add the -L/opt/local/lib directly in your final rule:

client: client.o Packet.o
    g++ -L/opt/local/lib -o client client.o Packet.o -lboost_system

The -I only tells the compiler where header files are, the linker needs libraries and you use -L for that.

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