在编写跨平台的代码时,我们往往需要用到条件编译的宏,以便让同一套代码兼容编译器不同版本、不同操作系统,下面就介绍下这些宏。
每个编译器都会自带一些预定义宏,以下拿gcc和VC++举例:
在编译器众多的预定义宏中,肯定有一个是用于标识编译器版本的宏定义:
__GNUC__是用来定义gcc编译器的版本,我们可以使用如下代码来进行条件编译:
/* Test for GCC > 3.2.0 */
#if __GNUC__ > 3 || \
(__GNUC__ == 3 && (__GNUC_MINOR__ > 2 || \
(__GNUC_MINOR__ == 2 && \
__GNUC_PATCHLEVEL__ > 0))
Another approach is to use the predefined macros to calculate a single number, then compare that against a threshold:
#define GCC_VERSION (__GNUC__ * 10000 \
+ __GNUC_MINOR__ * 100 \
+ __GNUC_PATCHLEVEL__)
/* Test for GCC > 3.2.0 */
#if GCC_VERSION > 30200
_MSC_VER是微软公司推出的C/C++编译器在ANSI/ISO C99标准之外扩展的宏定义,用来定义当前微软公司自己的编译器的主版本。下面是一些编译器版本的_MSC_VER值:
MSVC++ 14.1 _MSC_VER == 1910 (Visual Studio 2017)
MSVC++ 14.0 _MSC_VER == 1900 (Visual Studio 2015)
MSVC++ 12.0 _MSC_VER == 1800 (Visual Studio 2013)
MSVC++ 11.0 _MSC_VER == 1700 (Visual Studio 2012)
MSVC++ 10.0 _MSC_VER == 1600 (Visual Studio 2010)
MSVC++ 9.0 _MSC_VER == 1500 (Visual Studio 2008)
MSVC++ 8.0 _MSC_VER == 1400 (Visual Studio 2005)
MSVC++ 7.1 _MSC_VER == 1310 (Visual Studio 2003)
MSVC++ 7.0 _MSC_VER == 1300
MSVC++ 6.0 _MSC_VER == 1200
MSVC++ 5.0 _MSC_VER == 1100
其中MS VC++ 14.0表示Visual C++的版本为14.0,后面括号中的Visual Studio 2015,表明该VC++包含在微软开发工具Visual Studio 2015中。
/* Test for MSVC++ > Microsoft Visual Studio 2010 */
#if _MSC_VER > 1600
可以参考QtCore/qsystemdetection.h文件:
#ifndef QSYSTEMDETECTION_H
#define QSYSTEMDETECTION_H
/*
The operating system, must be one of: (Q_OS_x)
DARWIN - Any Darwin system
MAC - OS X and iOS
OSX - OS X
IOS - iOS
MSDOS - MS-DOS and Windows
OS2 - OS/2
OS2EMX - XFree86 on OS/2 (not PM)
WIN32 - Win32 (Windows 2000/XP/Vista/7 and Windows Server 2003/2008)
WINCE - WinCE (Windows CE 5.0)
WINRT - WinRT (Windows 8 Runtime)
CYGWIN - Cygwin
SOLARIS - Sun Solaris
HPUX - HP-UX
ULTRIX - DEC Ultrix
LINUX - Linux [has variants]
FREEBSD - FreeBSD [has variants]
NETBSD - NetBSD
OPENBSD - OpenBSD
BSDI - BSD/OS
IRIX - SGI Irix
OSF - HP Tru64 UNIX
SCO - SCO OpenServer 5
UNIXWARE - UnixWare 7, Open UNIX 8
AIX - AIX
HURD - GNU Hurd
DGUX - DG/UX
RELIANT - Reliant UNIX
DYNIX - DYNIX/ptx
QNX - QNX [has variants]
QNX6 - QNX RTP 6.1
LYNX - LynxOS
BSD4 - Any BSD 4.4 system
UNIX - Any UNIX BSD/SYSV system
ANDROID - Android platform
HAIKU - Haiku
The following operating systems have variants:
LINUX - both Q_OS_LINUX and Q_OS_ANDROID are defined when building for Android
- only Q_OS_LINUX is defined if building for other Linux systems
QNX - both Q_OS_QNX and Q_OS_BLACKBERRY are defined when building for Blackberry 10
- only Q_OS_QNX is defined if building for other QNX targets
FREEBSD - Q_OS_FREEBSD is defined only when building for FreeBSD with a BSD userland
- Q_OS_FREEBSD_KERNEL is always defined on FreeBSD, even if the userland is from GNU
*/
#if defined(__APPLE__) && (defined(__GNUC__) || defined(__xlC__) || defined(__xlc__))
# define Q_OS_DARWIN
# define Q_OS_BSD4
# ifdef __LP64__
# define Q_OS_DARWIN64
# else
# define Q_OS_DARWIN32
# endif
#elif defined(ANDROID)
# define Q_OS_ANDROID
# define Q_OS_LINUX
#elif defined(__CYGWIN__)
# define Q_OS_CYGWIN
#elif !defined(SAG_COM) && (!defined(WINAPI_FAMILY) || WINAPI_FAMILY==WINAPI_FAMILY_DESKTOP_APP) && (defined(WIN64) || defined(_WIN64) || defined(__WIN64__))
# define Q_OS_WIN32
# define Q_OS_WIN64
#elif !defined(SAG_COM) && (defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__))
# if defined(WINCE) || defined(_WIN32_WCE)
# define Q_OS_WINCE
# elif defined(WINAPI_FAMILY)
# if defined(WINAPI_FAMILY_PHONE_APP) && WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP
# define Q_OS_WINPHONE
# define Q_OS_WINRT
# elif WINAPI_FAMILY==WINAPI_FAMILY_APP
# define Q_OS_WINRT
# else
# define Q_OS_WIN32
# endif
# else
# define Q_OS_WIN32
# endif
#elif defined(__sun) || defined(sun)
# define Q_OS_SOLARIS
#elif defined(hpux) || defined(__hpux)
# define Q_OS_HPUX
#elif defined(__ultrix) || defined(ultrix)
# define Q_OS_ULTRIX
#elif defined(sinix)
# define Q_OS_RELIANT
#elif defined(__native_client__)
# define Q_OS_NACL
#elif defined(__linux__) || defined(__linux)
# define Q_OS_LINUX
#elif defined(__FreeBSD__) || defined(__DragonFly__) || defined(__FreeBSD_kernel__)
# ifndef __FreeBSD_kernel__
# define Q_OS_FREEBSD
# endif
# define Q_OS_FREEBSD_KERNEL
# define Q_OS_BSD4
#elif defined(__NetBSD__)
# define Q_OS_NETBSD
# define Q_OS_BSD4
#elif defined(__OpenBSD__)
# define Q_OS_OPENBSD
# define Q_OS_BSD4
#elif defined(__bsdi__)
# define Q_OS_BSDI
# define Q_OS_BSD4
#elif defined(__sgi)
# define Q_OS_IRIX
#elif defined(__osf__)
# define Q_OS_OSF
#elif defined(_AIX)
# define Q_OS_AIX
#elif defined(__Lynx__)
# define Q_OS_LYNX
#elif defined(__GNU__)
# define Q_OS_HURD
#elif defined(__DGUX__)
# define Q_OS_DGUX
#elif defined(__QNXNTO__)
# define Q_OS_QNX
#elif defined(_SEQUENT_)
# define Q_OS_DYNIX
#elif defined(_SCO_DS) /* SCO OpenServer 5 + GCC */
# define Q_OS_SCO
#elif defined(__USLC__) /* all SCO platforms + UDK or OUDK */
# define Q_OS_UNIXWARE
#elif defined(__svr4__) && defined(i386) /* Open UNIX 8 + GCC */
# define Q_OS_UNIXWARE
#elif defined(__INTEGRITY)
# define Q_OS_INTEGRITY
#elif defined(VXWORKS) /* there is no "real" VxWorks define - this has to be set in the mkspec! */
# define Q_OS_VXWORKS
#elif defined(__HAIKU__)
# define Q_OS_HAIKU
#elif defined(__MAKEDEPEND__)
#else
# error "Qt has not been ported to this OS - see http://www.qt-project.org/"
#endif
#if defined(Q_OS_WIN32) || defined(Q_OS_WIN64) || defined(Q_OS_WINCE) || defined(Q_OS_WINRT)
# define Q_OS_WIN
#endif
#if defined(Q_OS_DARWIN)
# define Q_OS_MAC
# if defined(Q_OS_DARWIN64)
# define Q_OS_MAC64
# elif defined(Q_OS_DARWIN32)
# define Q_OS_MAC32
# endif
# include <TargetConditionals.h>
# if defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
# define Q_OS_IOS
# elif defined(TARGET_OS_MAC) && TARGET_OS_MAC
# define Q_OS_OSX
# define Q_OS_MACX // compatibility synonym
# endif
#endif
#if defined(Q_OS_WIN)
# undef Q_OS_UNIX
#elif !defined(Q_OS_UNIX)
# define Q_OS_UNIX
#endif
#ifdef Q_OS_DARWIN
# include <Availability.h>
# include <AvailabilityMacros.h>
#
# ifdef Q_OS_OSX
# if !defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_6
# undef __MAC_OS_X_VERSION_MIN_REQUIRED
# define __MAC_OS_X_VERSION_MIN_REQUIRED __MAC_10_6
# endif
# if !defined(MAC_OS_X_VERSION_MIN_REQUIRED) || MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6
# undef MAC_OS_X_VERSION_MIN_REQUIRED
# define MAC_OS_X_VERSION_MIN_REQUIRED MAC_OS_X_VERSION_10_6
# endif
# endif
#
# // Numerical checks are preferred to named checks, but to be safe
# // we define the missing version names in case Qt uses them.
#
# if !defined(__MAC_10_7)
# define __MAC_10_7 1070
# endif
# if !defined(__MAC_10_8)
# define __MAC_10_8 1080
# endif
# if !defined(__MAC_10_9)
# define __MAC_10_9 1090
# endif
# if !defined(__MAC_10_10)
# define __MAC_10_10 101000
# endif
# if !defined(__MAC_10_11)
# define __MAC_10_11 101100
# endif
# if !defined(MAC_OS_X_VERSION_10_7)
# define MAC_OS_X_VERSION_10_7 1070
# endif
# if !defined(MAC_OS_X_VERSION_10_8)
# define MAC_OS_X_VERSION_10_8 1080
# endif
# if !defined(MAC_OS_X_VERSION_10_9)
# define MAC_OS_X_VERSION_10_9 1090
# endif
# if !defined(MAC_OS_X_VERSION_10_10)
# define MAC_OS_X_VERSION_10_10 101000
# endif
# if !defined(MAC_OS_X_VERSION_10_11)
# define MAC_OS_X_VERSION_10_11 101100
# endif
#
# if !defined(__IPHONE_4_3)
# define __IPHONE_4_3 40300
# endif
# if !defined(__IPHONE_5_0)
# define __IPHONE_5_0 50000
# endif
# if !defined(__IPHONE_5_1)
# define __IPHONE_5_1 50100
# endif
# if !defined(__IPHONE_6_0)
# define __IPHONE_6_0 60000
# endif
# if !defined(__IPHONE_6_1)
# define __IPHONE_6_1 60100
# endif
# if !defined(__IPHONE_7_0)
# define __IPHONE_7_0 70000
# endif
# if !defined(__IPHONE_7_1)
# define __IPHONE_7_1 70100
# endif
# if !defined(__IPHONE_8_0)
# define __IPHONE_8_0 80000
# endif
# if !defined(__IPHONE_8_1)
# define __IPHONE_8_1 80100
# endif
# if !defined(__IPHONE_8_2)
# define __IPHONE_8_2 80200
# endif
# if !defined(__IPHONE_8_3)
# define __IPHONE_8_3 80300
# endif
# if !defined(__IPHONE_8_4)
# define __IPHONE_8_4 80400
# endif
# if !defined(__IPHONE_9_0)
# define __IPHONE_9_0 90000
# endif
#endif
#ifdef __LSB_VERSION__
# if __LSB_VERSION__ < 40
# error "This version of the Linux Standard Base is unsupported"
# endif
#ifndef QT_LINUXBASE
# define QT_LINUXBASE
#endif
#endif
#endif // QSYSTEMDETECTION_H