问题
I\'m porting a relatively simple console program written for Unix to the Windows platform (Visual C++ 8.0). All the source files include \"unistd.h\", which doesn\'t exist. Removing it, I get complaints about misssing prototypes for \'srandom\', \'random\', and \'getopt\'. I know I can replace the random functions, and I\'m pretty sure I can find/hack-up a getopt implementation.
But I\'m sure others have run into the same challenge. My question is: is there a port of \"unistd.h\" to Windows? At least one containg those functions which do have a native Windows implementation - I don\'t need pipes or forking.
EDIT:
I know I can create my very own \"unistd.h\" which contains replacements for the things I need - especially in this case, since it is a limited set. But since it seems like a common problem, I was wondering if someone had done the work already for a bigger subset of the functionality.
Switching to a different compiler or environment isn\'t possible at work - I\'m stuck with Visual Studio.
回答1:
Since we can't find a version on the Internet, let's start one here.
Most ports to Windows probably only need a subset of the complete Unix file.
Here's a starting point. Please add definitions as needed.
#ifndef _UNISTD_H
#define _UNISTD_H 1
/* This is intended as a drop-in replacement for unistd.h on Windows.
* Please add functionality as neeeded.
* https://stackoverflow.com/a/826027/1202830
*/
#include <stdlib.h>
#include <io.h>
#include <getopt.h> /* getopt at: https://gist.github.com/ashelly/7776712 */
#include <process.h> /* for getpid() and the exec..() family */
#include <direct.h> /* for _getcwd() and _chdir() */
#define srandom srand
#define random rand
/* Values for the second argument to access.
These may be OR'd together. */
#define R_OK 4 /* Test for read permission. */
#define W_OK 2 /* Test for write permission. */
//#define X_OK 1 /* execute permission - unsupported in windows*/
#define F_OK 0 /* Test for existence. */
#define access _access
#define dup2 _dup2
#define execve _execve
#define ftruncate _chsize
#define unlink _unlink
#define fileno _fileno
#define getcwd _getcwd
#define chdir _chdir
#define isatty _isatty
#define lseek _lseek
/* read, write, and close are NOT being #defined here, because while there are file handle specific versions for Windows, they probably don't work for sockets. You need to look at your app and consider whether to call e.g. closesocket(). */
#ifdef _WIN64
#define ssize_t __int64
#else
#define ssize_t long
#endif
#define STDIN_FILENO 0
#define STDOUT_FILENO 1
#define STDERR_FILENO 2
/* should be in some equivalent to <sys/types.h> */
typedef __int8 int8_t;
typedef __int16 int16_t;
typedef __int32 int32_t;
typedef __int64 int64_t;
typedef unsigned __int8 uint8_t;
typedef unsigned __int16 uint16_t;
typedef unsigned __int32 uint32_t;
typedef unsigned __int64 uint64_t;
#endif /* unistd.h */
回答2:
Try including the io.h file. It seems to be the Visual Studio's equivalent of unistd.h.
I hope this helps.
回答3:
I would recommend using mingw/msys as a development environment. Especially if you are porting simple console programs. Msys implements a Unix-like shell on Windows, and mingw is a port of the GNU compiler collection (GCC) and other GNU build tools to the Windows platform. It is an open-source project, and well-suited to the task. I currently use it to build utility programs and console applications for Windows XP, and it most certainly has that unistd.h header you are looking for.
The install procedure can be a little bit tricky, but I found that the best place to start is in MSYS.
回答4:
I stumbled on this thread while trying to find a Windows alternative for getpid() (defined in unistd.h). It turns out that including process.h does the trick. Maybe this helps people who find this thread in the future.
回答5:
No, IIRC there is no getopt() on Windows.
Boost, however, has the program_options library... which works okay. It will seem like overkill at first, but it isn't terrible, especially considering it can handle setting program options in configuration files and environment variables in addition to command line options.
回答6:
MinGW 4.x has unistd.h in \MinGW\include, \MinGW\include\sys and \MinGW\lib\gcc\mingw32\4.6.2\include\ssp
Here is the code for the MinGW version, by Rob Savoye; modified by Earnie Boyd, Danny Smith, Ramiro Polla, Gregory McGarry and Keith Marshall:
/*
* unistd.h
*
* Standard header file declaring MinGW's POSIX compatibility features.
*
* $Id: unistd.h,v c3ebd36f8211 2016/02/16 16:05:39 keithmarshall $
*
* Written by Rob Savoye <rob@cygnus.com>
* Modified by Earnie Boyd <earnie@users.sourceforge.net>
* Danny Smith <dannysmith@users.sourceforge.net>
* Ramiro Polla <ramiro@lisha.ufsc.br>
* Gregory McGarry <gregorymcgarry@users.sourceforge.net>
* Keith Marshall <keithmarshall@users.sourceforge.net>
* Copyright (C) 1997, 1999, 2002-2004, 2007-2009, 2014-2016,
* MinGW.org Project.
*
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice, this permission notice, and the following
* disclaimer shall be included in all copies or substantial portions of
* the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OF OR OTHER
* DEALINGS IN THE SOFTWARE.
*
*/
#ifndef _UNISTD_H
#define _UNISTD_H 1
#pragma GCC system_header
/* All MinGW headers MUST include _mingw.h before anything else,
* to ensure proper initialization of feature test macros.
*/
#include <_mingw.h>
/* unistd.h maps (roughly) to Microsoft's <io.h>
* Other headers included by <unistd.h> may be selectively processed;
* __UNISTD_H_SOURCED__ enables such selective processing.
*/
#define __UNISTD_H_SOURCED__ 1
#include <io.h>
#include <process.h>
#include <getopt.h>
/* These are defined in stdio.h. POSIX also requires that they
* are to be consistently defined here; don't guard against prior
* definitions, as this might conceal inconsistencies.
*/
#define SEEK_SET 0
#define SEEK_CUR 1
#define SEEK_END 2
#if _POSIX_C_SOURCE
/* POSIX process/thread suspension functions; all are supported by a
* common MinGW API in libmingwex.a, providing for suspension periods
* ranging from mean values of ~7.5 milliseconds, (see the comments in
* <time.h>), extending up to a maximum of ~136 years.
*
* Note that, whereas POSIX supports early wake-up of any suspended
* process/thread, in response to a signal, this implementation makes
* no attempt to emulate this signalling behaviour, (since signals are
* not well supported by Windows); thus, unless impeded by an invalid
* argument, this implementation always returns an indication as if
* the sleeping period ran to completion.
*/
_BEGIN_C_DECLS
__cdecl __MINGW_NOTHROW
int __mingw_sleep( unsigned long, unsigned long );
/* The nanosleep() function provides the most general purpose API for
* process/thread suspension; it is declared in <time.h>, (where it is
* accompanied by an in-line implementation), rather than here, and it
* provides for specification of suspension periods in the range from
* ~7.5 ms mean, (on WinNT derivatives; ~27.5 ms on Win9x), extending
* up to ~136 years, (effectively eternity).
*
* The usleep() function, and its associated useconds_t type specifier
* were made obsolete in POSIX.1-2008; declared here, only for backward
* compatibility, its continued use is not recommended. (It is limited
* to specification of suspension periods ranging from ~7.5 ms mean up
* to a maximum of 999,999 microseconds only).
*/
typedef unsigned long useconds_t __MINGW_ATTRIB_DEPRECATED;
int __cdecl __MINGW_NOTHROW usleep( useconds_t )__MINGW_ATTRIB_DEPRECATED;
#ifndef __NO_INLINE__
__CRT_INLINE __LIBIMPL__(( FUNCTION = usleep ))
int usleep( useconds_t period ){ return __mingw_sleep( 0, 1000 * period ); }
#endif
/* The sleep() function is, perhaps, the most commonly used of all the
* process/thread suspension APIs; it provides support for specification
* of suspension periods ranging from 1 second to ~136 years. (However,
* POSIX recommends limiting the maximum period to 65535 seconds, to
* maintain portability to platforms with only 16-bit ints).
*/
unsigned __cdecl __MINGW_NOTHROW sleep( unsigned );
#ifndef __NO_INLINE__
__CRT_INLINE __LIBIMPL__(( FUNCTION = sleep ))
unsigned sleep( unsigned period ){ return __mingw_sleep( period, 0 ); }
#endif
/* POSIX ftruncate() function.
*
* Microsoft's _chsize() function is incorrectly described, on MSDN,
* as a preferred replacement for the POSIX chsize() function. There
* never was any such POSIX function; the actual POSIX equivalent is
* the ftruncate() function.
*/
int __cdecl ftruncate( int, off_t );
#ifndef __NO_INLINE__
__CRT_INLINE __JMPSTUB__(( FUNCTION = ftruncate, REMAPPED = _chsize ))
int ftruncate( int __fd, off_t __length ){ return _chsize( __fd, __length ); }
#endif
_END_C_DECLS
#endif /* _POSIX_C_SOURCE */
#undef __UNISTD_H_SOURCED__
#endif /* ! _UNISTD_H: $RCSfile: unistd.h,v $: end of file */
This file requires the inclusion of _mingw.h, which is as follows:
#ifndef __MINGW_H
/*
* _mingw.h
*
* MinGW specific macros included by ALL mingwrt include files; (this file
* is part of the MinGW32 runtime library package).
*
* $Id: _mingw.h.in,v 7daa0459f602 2016/05/03 17:40:54 keithmarshall $
*
* Written by Mumit Khan <khan@xraylith.wisc.edu>
* Copyright (C) 1999, 2001-2011, 2014-2016, MinGW.org Project
*
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
*/
#define __MINGW_H
/* In previous versions, __MINGW32_VERSION was expressed as a dotted
* numeric pair, representing major.minor; unfortunately, this doesn't
* adapt well to the inclusion of a patch-level component, since the
* major.minor.patch dotted triplet representation is not valid as a
* numeric entity. Thus, for this version, we adopt a representation
* which encodes the version as a long integer value, expressing:
*
* __MINGW32_VERSION = 1,000,000 * major + 1,000 * minor + patch
*
* DO NOT EDIT these package version assignments manually; they are
* derived from the package version specification within configure.ac,
* whence they are propagated automatically, at package build time.
*/
#define __MINGW32_VERSION 3022001L
#define __MINGW32_MAJOR_VERSION 3
#define __MINGW32_MINOR_VERSION 22
#define __MINGW32_PATCHLEVEL 1
#if __GNUC__ >= 3 && ! defined __PCC__
#pragma GCC system_header
#endif
#ifndef _MSVCRTVER_H
/* Legacy versions of mingwrt use the macro __MSVCRT_VERSION__ to
* enable evolving features of different MSVCRT.DLL versions. This
* usage is no longer recommended, but the __MSVCRT_VERSION__ macro
* remains useful when a non-freely distributable MSVCRxx.DLL is to
* be substituted for MSVCRT.DLL; for such usage, the substitute
* MSVCRxx.DLL may be identified as specified in...
*/
# include <msvcrtver.h>
#endif
/* A better inference than __MSVCRT_VERSION__, of the capabilities
* supported by the operating system default MSVCRT.DLL, is provided
* by the Windows API version identification macros.
*/
#include <w32api.h>
/* The following are defined by the user (or by the compiler), to specify how
* identifiers are imported from a DLL. All headers should include this first,
* and then use __DECLSPEC_SUPPORTED to choose between the old ``__imp__name''
* style or the __MINGW_IMPORT style for declarations.
*
* __DECLSPEC_SUPPORTED Defined if dllimport attribute is supported.
* __MINGW_IMPORT The attribute definition to specify imported
* variables/functions.
* _CRTIMP As above. For MS compatibility.
*
* Macros to enable MinGW features which deviate from standard MSVC
* compatible behaviour; these may be specified directly in user code,
* activated implicitly, (e.g. by specifying _POSIX_C_SOURCE or such),
* or by inclusion in __MINGW_FEATURES__:
*
* __USE_MINGW_ANSI_STDIO Select a more ANSI C99 compatible
* implementation of printf() and friends;
* (users should not set this directly).
*
* Other macros:
*
* __int64 define to be long long. Using a typedef
* doesn't work for "unsigned __int64"
*
*
* Manifest definitions for flags to control globbing of the command line
* during application start up, (before main() is called). The first pair,
* when assigned as bit flags within _CRT_glob, select the globbing algorithm
* to be used; (the MINGW algorithm overrides MSCVRT, if both are specified).
* Prior to mingwrt-3.21, only the MSVCRT option was supported; this choice
* may produce different results, depending on which particular version of
* MSVCRT.DLL is in use; (in recent versions, it seems to have become
* definitively broken, when globbing within double quotes).
*/
#define __CRT_GLOB_USE_MSVCRT__ 0x0001
/* From mingwrt-3.21 onward, this should be the preferred choice; it will
* produce consistent results, regardless of the MSVCRT.DLL version in use.
*/
#define __CRT_GLOB_USE_MINGW__ 0x0002
/* When the __CRT_GLOB_USE_MINGW__ flag is set, within _CRT_glob, the
* following additional options are also available; they are not enabled
* by default, but the user may elect to enable any combination of them,
* by setting _CRT_glob to the boolean sum (i.e. logical OR combination)
* of __CRT_GLOB_USE_MINGW__ and the desired options.
*
* __CRT_GLOB_USE_SINGLE_QUOTE__ allows use of single (apostrophe)
* quoting characters, analogously to
* POSIX usage, as an alternative to
* double quotes, for collection of
* arguments separated by white space
* into a single logical argument.
*
* __CRT_GLOB_BRACKET_GROUPS__ enable interpretation of bracketed
* character groups as POSIX compatible
* globbing patterns, matching any one
* character which is either included
* in, or excluded from the group.
*
* __CRT_GLOB_CASE_SENSITIVE__ enable case sensitive matching for
* globbing patterns; this is default
* behaviour for POSIX, but because of
* the case insensitive nature of the
* MS-Windows file system, it is more
* appropriate to use case insensitive
* globbing as the MinGW default.
*
*/
#define __CRT_GLOB_USE_SINGLE_QUOTE__ 0x0010
#define __CRT_GLOB_BRACKET_GROUPS__ 0x0020
#define __CRT_GLOB_CASE_SENSITIVE__ 0x0040
/* The MinGW globbing algorithm uses the ASCII DEL control code as a marker
* for globbing characters which were embedded within quoted arguments; (the
* quotes are stripped away BEFORE the argument is globbed; the globbing code
* treats the marked character as immutable, and strips out the DEL markers,
* before storing the resultant argument). The DEL code is mapped to this
* function here; DO NOT change it, without rebuilding the runtime.
*/
#define __CRT_GLOB_ESCAPE_CHAR__ (char)(127)
/* Manifest definitions identifying the flag bits, controlling activation
* of MinGW features, as specified by the user in __MINGW_FEATURES__.
*/
#define __MINGW_ANSI_STDIO__ 0x0000000000000001ULL
/*
* The following three are not yet formally supported; they are
* included here, to document anticipated future usage.
*/
#define __MINGW_LC_EXTENSIONS__ 0x0000000000000050ULL
#define __MINGW_LC_MESSAGES__ 0x0000000000000010ULL
#define __MINGW_LC_ENVVARS__ 0x0000000000000040ULL
/* Try to avoid problems with outdated checks for GCC __attribute__ support.
*/
#undef __attribute__
#if defined (__PCC__)
# undef __DECLSPEC_SUPPORTED
# ifndef __MINGW_IMPORT
# define __MINGW_IMPORT extern
# endif
# ifndef _CRTIMP
# define _CRTIMP
# endif
# ifndef __cdecl
# define __cdecl _Pragma("cdecl")
# endif
# ifndef __stdcall
# define __stdcall _Pragma("stdcall")
# endif
# ifndef __int64
# define __int64 long long
# endif
# ifndef __int32
# define __int32 long
# endif
# ifndef __int16
# define __int16 short
# endif
# ifndef __int8
# define __int8 char
# endif
# ifndef __small
# define __small char
# endif
# ifndef __hyper
# define __hyper long long
# endif
# ifndef __volatile__
# define __volatile__ volatile
# endif
# ifndef __restrict__
# define __restrict__ restrict
# endif
# define NONAMELESSUNION
#elif defined(__GNUC__)
# ifdef __declspec
# ifndef __MINGW_IMPORT
/* Note the extern. This is needed to work around GCC's
limitations in handling dllimport attribute. */
# define __MINGW_IMPORT extern __attribute__((__dllimport__))
# endif
# ifndef _CRTIMP
# ifdef __USE_CRTIMP
# define _CRTIMP __attribute__((dllimport))
# else
# define _CRTIMP
# endif
# endif
# define __DECLSPEC_SUPPORTED
# else /* __declspec */
# undef __DECLSPEC_SUPPORTED
# undef __MINGW_IMPORT
# ifndef _CRTIMP
# define _CRTIMP
# endif
# endif /* __declspec */
/*
* The next two defines can cause problems if user code adds the
* __cdecl attribute like so:
* void __attribute__ ((__cdecl)) foo(void);
*/
# ifndef __cdecl
# define __cdecl __attribute__((__cdecl__))
# endif
# ifndef __stdcall
# define __stdcall __attribute__((__stdcall__))
# endif
# ifndef __int64
# define __int64 long long
# endif
# ifndef __int32
# define __int32 long
# endif
# ifndef __int16
# define __int16 short
# endif
# ifndef __int8
# define __int8 char
# endif
# ifndef __small
# define __small char
# endif
# ifndef __hyper
# define __hyper long long
# endif
#else /* ! __GNUC__ && ! __PCC__ */
# ifndef __MINGW_IMPORT
# define __MINGW_IMPORT __declspec(dllimport)
# endif
# ifndef _CRTIMP
# define _CRTIMP __declspec(dllimport)
# endif
# define __DECLSPEC_SUPPORTED
# define __attribute__(x) /* nothing */
#endif
#if defined (__GNUC__) && defined (__GNUC_MINOR__)
#define __MINGW_GNUC_PREREQ(major, minor) \
(__GNUC__ > (major) \
|| (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
#else
#define __MINGW_GNUC_PREREQ(major, minor) 0
#endif
#ifdef __cplusplus
# define __CRT_INLINE inline
#else
# if __GNUC_STDC_INLINE__
# define __CRT_INLINE extern inline __attribute__((__gnu_inline__))
# else
# define __CRT_INLINE extern __inline__
# endif
#endif
# ifdef __GNUC__
/* A special form of __CRT_INLINE is provided; it will ALWAYS request
* inlining when possible. Originally specified as _CRTALIAS, this is
* now deprecated in favour of __CRT_ALIAS, for syntactic consistency
* with __CRT_INLINE itself.
*/
# define _CRTALIAS __CRT_INLINE __attribute__((__always_inline__))
# define __CRT_ALIAS __CRT_INLINE __attribute__((__always_inline__))
# else
# define _CRTALIAS __CRT_INLINE /* deprecated form */
# define __CRT_ALIAS __CRT_INLINE /* preferred form */
# endif
/*
* Each function which is implemented as a __CRT_ALIAS should also be
* accompanied by an externally visible interface. The following pair
* of macros provide a mechanism for implementing this, either as a stub
* redirecting to an alternative external function, or by compilation of
* the normally inlined code into free standing object code; each macro
* provides a way for us to offer arbitrary hints for use by the build
* system, while remaining transparent to the compiler.
*/
#define __JMPSTUB__(__BUILD_HINT__)
#define __LIBIMPL__(__BUILD_HINT__)
#ifdef __cplusplus
# define __UNUSED_PARAM(x)
#else
# ifdef __GNUC__
# define __UNUSED_PARAM(x) x __attribute__((__unused__))
# else
# define __UNUSED_PARAM(x) x
# endif
#endif
#ifdef __GNUC__
#define __MINGW_ATTRIB_NORETURN __attribute__((__noreturn__))
#define __MINGW_ATTRIB_CONST __attribute__((__const__))
#else
#define __MINGW_ATTRIB_NORETURN
#define __MINGW_ATTRIB_CONST
#endif
#if __MINGW_GNUC_PREREQ (3, 0)
#define __MINGW_ATTRIB_MALLOC __attribute__((__malloc__))
#define __MINGW_ATTRIB_PURE __attribute__((__pure__))
#else
#define __MINGW_ATTRIB_MALLOC
#define __MINGW_ATTRIB_PURE
#endif
/* Attribute `nonnull' was valid as of gcc 3.3. We don't use GCC's
variadiac macro facility, because variadic macros cause syntax
errors with --traditional-cpp. */
#if __MINGW_GNUC_PREREQ (3, 3)
#define __MINGW_ATTRIB_NONNULL(arg) __attribute__((__nonnull__(arg)))
#else
#define __MINGW_ATTRIB_NONNULL(arg)
#endif /* GNUC >= 3.3 */
#if __MINGW_GNUC_PREREQ (3, 1)
#define __MINGW_ATTRIB_DEPRECATED __attribute__((__deprecated__))
#else
#define __MINGW_ATTRIB_DEPRECATED
#endif /* GNUC >= 3.1 */
#if __MINGW_GNUC_PREREQ (3, 3)
#define __MINGW_NOTHROW __attribute__((__nothrow__))
#else
#define __MINGW_NOTHROW
#endif /* GNUC >= 3.3 */
/* TODO: Mark (almost) all CRT functions as __MINGW_NOTHROW. This will
allow GCC to optimize away some EH unwind code, at least in DW2 case. */
/* Activation of MinGW specific extended features:
*/
#ifndef __USE_MINGW_ANSI_STDIO
/* Users should not set this directly; rather, define one (or more)
* of the feature test macros (tabulated below), or specify any of the
* compiler's command line options, (e.g. -posix, -ansi, or -std=c...),
* which cause _POSIX_SOURCE, or __STRICT_ANSI__ to be defined.
*
* We must check this BEFORE we specifiy any implicit _POSIX_C_SOURCE,
* otherwise we would always implicitly choose __USE_MINGW_ANSI_STDIO,
* even if none of these selectors are specified explicitly...
*/
# if defined __STRICT_ANSI__ || defined _ISOC99_SOURCE \
|| defined _POSIX_SOURCE || defined _POSIX_C_SOURCE \
|| defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED \
|| defined _GNU_SOURCE || defined _BSD_SOURCE \
|| defined _SVID_SOURCE
/*
* but where any of these source code qualifiers are specified,
* then assume ANSI I/O standards are preferred over Microsoft's...
*/
# define __USE_MINGW_ANSI_STDIO 1
# else
/* otherwise use whatever __MINGW_FEATURES__ specifies...
*/
# define __USE_MINGW_ANSI_STDIO (__MINGW_FEATURES__ & __MINGW_ANSI_STDIO__)
# endif
#endif
#ifndef _POSIX_C_SOURCE
/* Users may define this, either directly or indirectly, to explicitly
* enable a particular level of visibility for the subset of those POSIX
* features which are supported by MinGW; (notice that this offers no
* guarantee that any particular POSIX feature will be supported).
*/
# if defined _XOPEN_SOURCE
/* Specifying this is the preferred method for setting _POSIX_C_SOURCE;
* (POSIX defines an explicit relationship to _XOPEN_SOURCE). Note that
* any such explicit setting will augment the set of features which are
* available to any compilation unit, even if it seeks to be strictly
* ANSI-C compliant.
*/
# if _XOPEN_SOURCE < 500
# define _POSIX_C_SOURCE 1L /* POSIX.1-1990 / SUSv1 */
# elif _XOPEN_SOURCE < 600
# define _POSIX_C_SOURCE 199506L /* POSIX.1-1996 / SUSv2 */
# elif _XOPEN_SOURCE < 700
# define _POSIX_C_SOURCE 200112L /* POSIX.1-2001 / SUSv3 */
# else
# define _POSIX_C_SOURCE 200809L /* POSIX.1-2008 / SUSv4 */
# endif
# elif defined _GNU_SOURCE || defined _BSD_SOURCE || ! defined __STRICT_ANSI__
/*
* No explicit level of support has been specified; implicitly grant
* the most comprehensive level to any compilation unit which requests
* either GNU or BSD feature support, or does not seek to be strictly
* ANSI-C compliant.
*/
# define _POSIX_C_SOURCE 200809L
# elif defined _POSIX_SOURCE
/* Now formally deprecated by POSIX, some old code may specify this;
* it will enable a minimal level of POSIX support, in addition to the
* limited feature set enabled for strict ANSI-C conformity.
*/
# define _POSIX_C_SOURCE 1L
# endif
#endif
#ifndef _ISOC99_SOURCE
/* libmingwex.a provides free-standing implementations for many of the
* functions which were introduced in C99; MinGW headers do not expose
* prototypes for these, unless this feature test macro is defined, by
* the user, or implied by other standards...
*/
# if __STDC_VERSION__ >= 199901L || _POSIX_C_SOURCE >= 200112L
# define _ISOC99_SOURCE 1
# endif
#endif
#if ! defined _MINGW32_SOURCE_EXTENDED && ! defined __STRICT_ANSI__
/*
* Enable mingw32 extensions by default, except when __STRICT_ANSI__
* conformity mode has been enabled.
*/
# define _MINGW32_SOURCE_EXTENDED 1
#endif
#endif /* __MINGW_H: $RCSfile: _mingw.h.in,v $: end of file */
The rest of the includes should be standard to your environment.
回答7:
Create your own unistd.h header and include the needed headers for function prototypes.
来源：https://stackoverflow.com/questions/341817/is-there-a-replacement-for-unistd-h-for-windows-visual-c