Question

这个clang ++错误消息是什么意思，为什么我得到它？我似乎无法在互联网上找到关于它的任何 ...... clang: warning: treating 'c-header' input as 'c++-header' when in C++ mode, this behavior is deprecated

这是我的代码，

MergeSort.h ：

#ifndef __MERGESORT_H__
#define __MERGESORT_H__

#include <iostream>
using namespace std;

class MergeSort;

class MergeSort
{
    public:

    MergeSort();
    MergeSort(const int* list, int length);
    ~MergeSort();

    friend ostream& operator<< (ostream& os, const MergeSort& ms);

    private:

    int* list;
    int len;
};

ostream& operator<< (ostream& os, const MergeSort& ms);
#endif

MergeSort.cpp ：

#include <iostream>
#include "MergeSort.h"

using namespace std;

MergeSort::MergeSort()
{
    list = new int[1];
    list[0] = 0;
    len = 0;
}

MergeSort::MergeSort (const int* t, int length)
{
    if (t) {
        len = length;
        list = new int[len];
        for (int i = 0; i < length; i++)
            list[i] = t[i];
    }
    else {
        list = new int[1];
        list[0] = 0;
        len = 0;
    }
}

MergeSort::~MergeSort()
{
    delete[] list;
}

ostream& operator<<(ostream& os, const MergeSort& ms)
{
    for (int i = 0; i < ms.len; i++)
        os << ms.list[i];
    return os;
}


int
main()
{
    int list[] = {1,2,3,4};
    int list_len = sizeof(list)/sizeof(int);
    MergeSort ms = MergeSort(list, list_len);
    cout << ms << endl;
    cout << "hello world" << endl;
}

输出：

[gyeh@gyeh mergesort]$ clang++ -c -g -Wall MergeSort.cpp MergeSort.h
clang: warning: treating 'c-header' input as 'c++-header' when in C++ mode, this behavior is deprecated
[gyeh@gyeh mergesort]$ clang++ MergeSort.o -o MergeSort
[gyeh@gyeh mergesort]$ valgrind --leak-check=yes ./MergeSort
==25774== Memcheck, a memory error detector
==25774== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==25774== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==25774== Command: ./MergeSort
==25774== 
1234
hello world
==25774== 
==25774== HEAP SUMMARY:
==25774==     in use at exit: 0 bytes in 0 blocks
==25774==   total heap usage: 1 allocs, 1 frees, 16 bytes allocated
==25774== 
==25774== All heap blocks were freed -- no leaks are possible
==25774== 
==25774== For counts of detected and suppressed errors, rerun with: -v
==25774== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 1 from 1)

Answer 1

您不应该编译头文件，只编译源文件。

Answer 2

从@JoachimPileborg启发。此错误消息的实际含义是：

您正在通过C编译器编译CXX头文件。它DOES NOT表示您CAN NOT编译标头文件。如果为正确的文件选择正确的编译器，则CAN编译标头文件。简单来说就是：

clang   with *.h    works
clang   with *.hpp  not works
clang++ with *.h    not works
clang++ with *.hpp  works

因此，要解决有关编译头文件的问题，例如预编译头文件，只需将后缀从.h更改为.hpp即可。

警告：处理＆＃39; c-header＆＃39;输入为＆＃39; c ++ - header＆＃39;在C ++模式下，不推荐使用此行为

2 个答案: