当C++在Linux上编译没有问题时，如何在Mac上正确编译呢？

Question

我正在处理一个由他人编写的C++项目，它可以在Linux上成功编译。在我将它克隆到Mac并执行'make‘之后，它给出了这个错误：

clang: error: unknown argument: '-mpreferred-stack-boundary=4'
make: *** [all] Error 1

在我的苹果电脑上，我安装了g++。然后，我从Makefile中删除了-m首选堆栈边界=4选项：

$(CC) $(CFLAGS) -mpreferred-stack-boundary=4 -mstackrealign  -o ${NAME}.so $(SEGSRC) $(CFILE) 

这些是Makefile中的一些定义：

CC                = /usr/bin/g++
CFLAGS    =   -D_ChaiScriptON -g -w -O0 -fPIC -shared -std=c++11

“c++11”是否意味着我应该在我的苹果电脑上安装c++11？我已经安装了g++。

我试着从命令中删除了-m首选栈边界=4，然后我给出了这个错误：

./CObjectRecognizer/include/commonsFun.h:15:10: fatal error: 'io.h' file not found
#include <io.h>
         ^~~~~~
1 error generated.

'io.h‘是否来自标准c库？

Answer 1

C++11是C++的一个版本。除非您的g++版本非常旧，否则它将毫无问题地支持C++11。

<io.h>是一个非标准头文件。您应该删除它，但不幸的是，它的存在可能意味着您试图编译的代码也是非标准的。在这种情况下，您可能很难让代码在不同的环境中工作。

编辑 clang使用C++11也不会有任何问题。

Answer 2

下面是linux上io.h的内容：

注意:这似乎是在x86-64硬件上运行时的特定于操作系统的文件。

/* Copyright (C) 1996-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _SYS_IO_H
#define _SYS_IO_H   1

#include <features.h>

__BEGIN_DECLS

/* If TURN_ON is TRUE, request for permission to do direct i/o on the
   port numbers in the range [FROM,FROM+NUM-1].  Otherwise, turn I/O
   permission off for that range.  This call requires root privileges.

   Portability note: not all Linux platforms support this call.  Most
   platforms based on the PC I/O architecture probably will, however.
   E.g., Linux/Alpha for Alpha PCs supports this.  */
extern int ioperm (unsigned long int __from, unsigned long int __num,
                   int __turn_on) __THROW;

/* Set the I/O privilege level to LEVEL.  If LEVEL>3, permission to
   access any I/O port is granted.  This call requires root
   privileges. */
extern int iopl (int __level) __THROW;

#if defined __GNUC__ && __GNUC__ >= 2

static __inline unsigned char
inb (unsigned short int __port)
{
  unsigned char _v;

  __asm__ __volatile__ ("inb %w1,%0":"=a" (_v):"Nd" (__port));
  return _v;
}

static __inline unsigned char
inb_p (unsigned short int __port)
{
  unsigned char _v;

  __asm__ __volatile__ ("inb %w1,%0\noutb %%al,$0x80":"=a" (_v):"Nd" (__port));
  return _v;
}

static __inline unsigned short int
inw (unsigned short int __port)
{
  unsigned short _v;

  __asm__ __volatile__ ("inw %w1,%0":"=a" (_v):"Nd" (__port));
  return _v;
}

static __inline unsigned short int
inw_p (unsigned short int __port)
{
  unsigned short int _v;

  __asm__ __volatile__ ("inw %w1,%0\noutb %%al,$0x80":"=a" (_v):"Nd" (__port));
  return _v;
}

static __inline unsigned int
inl (unsigned short int __port)
{
  unsigned int _v;

  __asm__ __volatile__ ("inl %w1,%0":"=a" (_v):"Nd" (__port));
  return _v;
}

static __inline unsigned int
inl_p (unsigned short int __port)
{
  unsigned int _v;
  __asm__ __volatile__ ("inl %w1,%0\noutb %%al,$0x80":"=a" (_v):"Nd" (__port));
  return _v;
}

static __inline void
outb (unsigned char __value, unsigned short int __port)
{
  __asm__ __volatile__ ("outb %b0,%w1": :"a" (__value), "Nd" (__port));
}

static __inline void
outb_p (unsigned char __value, unsigned short int __port)
{
  __asm__ __volatile__ ("outb %b0,%w1\noutb %%al,$0x80": :"a" (__value),
            "Nd" (__port));
}

static __inline void
outw (unsigned short int __value, unsigned short int __port)
{
  __asm__ __volatile__ ("outw %w0,%w1": :"a" (__value), "Nd" (__port));

}

static __inline void
outw_p (unsigned short int __value, unsigned short int __port)
{
  __asm__ __volatile__ ("outw %w0,%w1\noutb %%al,$0x80": :"a" (__value),
            "Nd" (__port));
}

static __inline void
outl (unsigned int __value, unsigned short int __port)
{
  __asm__ __volatile__ ("outl %0,%w1": :"a" (__value), "Nd" (__port));
}

static __inline void
outl_p (unsigned int __value, unsigned short int __port)
{
  __asm__ __volatile__ ("outl %0,%w1\noutb %%al,$0x80": :"a" (__value),
            "Nd" (__port));
}

static __inline void
insb (unsigned short int __port, void *__addr, unsigned long int __count)
{
  __asm__ __volatile__ ("cld ; rep ; insb":"=D" (__addr), "=c" (__count)
            :"d" (__port), "0" (__addr), "1" (__count));
}

static __inline void
insw (unsigned short int __port, void *__addr, unsigned long int __count)
{
  __asm__ __volatile__ ("cld ; rep ; insw":"=D" (__addr), "=c" (__count)
            :"d" (__port), "0" (__addr), "1" (__count));
}

static __inline void
insl (unsigned short int __port, void *__addr, unsigned long int __count)
{
  __asm__ __volatile__ ("cld ; rep ; insl":"=D" (__addr), "=c" (__count)
            :"d" (__port), "0" (__addr), "1" (__count));
}

static __inline void
outsb (unsigned short int __port, const void *__addr,
       unsigned long int __count)
{
  __asm__ __volatile__ ("cld ; rep ; outsb":"=S" (__addr), "=c" (__count)
            :"d" (__port), "0" (__addr), "1" (__count));
}

static __inline void
outsw (unsigned short int __port, const void *__addr,
       unsigned long int __count)
{
  __asm__ __volatile__ ("cld ; rep ; outsw":"=S" (__addr), "=c" (__count)
            :"d" (__port), "0" (__addr), "1" (__count));
}

static __inline void
outsl (unsigned short int __port, const void *__addr,
       unsigned long int __count)
{
  __asm__ __volatile__ ("cld ; rep ; outsl":"=S" (__addr), "=c" (__count)
            :"d" (__port), "0" (__addr), "1" (__count));
}

#endif  /* GNU C */

__END_DECLS
#endif /* _SYS_IO_H */