在angstrom上编写c/c++程序

Question

C和C++程序不在Angstrom上编译

C Progam (board.c)：

#include<stdio.h>
void main(){
    printf("hello world");
}

在Angstrom终端上编译C程序

root@pldek-beagle:~/Comparison# gcc board.c -o board
/usr/lib/gcc/arm-angstrom-linux-gnueabi/4.7.3/../../../../arm-angstrom-linux-gnueabi/bin/ld: this linker was not configured to use sysroots
collect2: error: ld returned 1 exit status


root@pldek-beagle:~/Comparison# gcc --sysroot=/usr/local  board.c -o board
board.c:1:18: fatal error: stdio.h: No such file or directory
compilation terminated.

root@pldek-beagle:~/Comparison# whereis stdio
stdio: /usr/include/stdio.h

root@pldek-beagle:~/Comparison# echo $PATH
/mnt/data/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/usr/include/c++/:/usr/include/:/usr/include/c++/:/usr/include/c++:/usr/include/c++/:/usr/include/c++/:/usr/include/c++/:/usr/include/:/usr/include

正如您在上面看到的，stdio.h路径在$PATH中是可用的，即使gcc无法找到它。

C++ Progam (beagle.cpp)：

using namespace std;
#include<iostream>
void main(){
    cout<<"hello world";
}

在Angstrom终端上编写C++程序

root@pldek-beagle:~/Comparison# g++ beagle.cpp -o beagle
/usr/lib/gcc/arm-angstrom-linux-gnueabi/4.7.3/../../../../arm-angstrom-linux-gnueabi/bin/ld: this linker was not configured to use sysroots
collect2: error: ld returned 1 exit status

root@pldek-beagle:~/Comparison# g++ --sysroot=/usr/local  beagle.cpp -o beagle
beagle.cpp:2:19: fatal error: iostream: No such file or directory
compilation terminated.

root@pldek-beagle:~/Comparison# whereis iostream
iostream: /usr/include/c++/iostream

echo $PATH
/mnt/data/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/usr/include/c++/:/usr/include/:/usr/include/c++/:/usr/include/c++:/usr/include/c++/:/usr/include/c++/:/usr/include/c++/:/usr/include/:/usr/include

正如您在上面看到的，iostream路径在$PATH中是可用的，即使这样，g++也无法找到它。

Answer 1

您不能仅仅期望获取任何随机的stdio.h文件。它是实现的一部分，对于交叉编译器来说，通常需要交叉编译器实现。<iostream>也一样。