我正在编写这个程序：
#include <iostream>
int main()
{
}
此命令
g++ -c hello_world.cpp
作品。
此命令
clang++ -c hello_world.cpp
给出了这个错误：
hello_world.cpp:1:10: fatal error: 'iostream' file not found
#include <iostream>
^
1 error generated.
这样做的：
clang++ -c hello_world.cpp -v
给出：
Ubuntu clang version 3.4-1ubuntu3 (tags/RELEASE_34/final) (based on LLVM 3.4)
Target: x86_64-pc-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.8.4
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.9.1
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8.4
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9.1
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8.4
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.1
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9
"/usr/bin/clang" -cc1 -triple x86_64-pc-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name hello_world.cpp -mrelocation-model static -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -target-linker-version 2.24 -v -coverage-file /home/user/code/cpp/StackOverflow_questions/hello_world.o -resource-dir /usr/bin/../lib/clang/3.4 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++ -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++/x86_64-linux-gnu -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++/backward -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/clang/3.4/include -internal-externc-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir /home/user/code/cpp/StackOverflow_questions -ferror-limit 19 -fmessage-length 202 -mstackrealign -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -vectorize-slp -o hello_world.o -x c++ hello_world.cpp
clang -cc1 version 3.4 based upon LLVM 3.4 default target x86_64-pc-linux-gnu
ignoring nonexistent directory "/usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++/x86_64-linux-gnu"
ignoring nonexistent directory "/usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++/backward"
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++
/usr/local/include
/usr/bin/../lib/clang/3.4/include
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
hello_world.cpp:1:10: fatal error: 'iostream' file not found
#include <iostream>
^
1 error generated.
clang ++正在谈论使用gcc 4.9的东西，但如果我这样做：
g ++ --version
输出：
g++ --version
g++ (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE
这是iostream在我的机器上的位置：
/usr/share/doc/fp-docs/2.6.2/fcl/iostream
/usr/include/boost/tr1/tr1/iostream
/usr/include/c++/4.8/iostream
答案 0 :(得分：2)
看到clang ++如何热衷于使用g ++ 4.9文件，我决定安装g ++ 4.9
ubuntu没有4.9作为正常的“sudo apt-get install g ++”的一部分。他们仍然在4.8。 （不确定是什么把gcc 4.9（但显然不是g ++ 4.9）放在我的系统上。）
我发现我可以通过以下方式安装g ++ 4.9：
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install g++-4.9
发出这些命令后，clang ++能够找到＆lt; iostream＆gt;。
答案 1 :(得分：-2)
尝试安装这些软件包，
sudo yum groupinstall "Development Tools"
sudo yum install libstdc++-static.x86_64 compat-libstdc++-33.x86_64
我遇到了这个问题，解决了安装这些软件包的问题。