When writing portable C++ code you need to write conditional code that depends on compiler used or the OS for which the code is written.
Here’s a typical case:
#if defined (_MSC_VER)
// code specific to Visual Studio compiler
#endif
To perform those checks you need to check pre-processor macros that various compilers set.
It can either be binary is defined vs. is not defined check (e.g. __APPLE__) or checking a value of the macro (e.g. _MSC_VER defines version of Visual Studio compiler).
This document describes macros set by various compilers.
Other documentations:
To check for which OS the code is compiled:
Linux and Linux-derived __linux__
Android __ANDROID__ (implies __linux__)
Linux (non-Android) __linux__ && !__ANDROID__
Darwin (Mac OS X and iOS) __APPLE__
Akaros (http://akaros.org) __ros__
Windows _WIN32
Windows 64 bit _WIN64 (implies _WIN32)
NaCL __native_client__
AsmJS __asmjs__
Fuschia __Fuchsia__
Checking the compiler:
To check which compiler is used:
Visual Studio _MSC_VER
gcc __GNUC__
clang __clang__
emscripten __EMSCRIPTEN__ (for asm.js and webassembly)
MinGW 32 __MINGW32__
MinGW-w64 32bit __MINGW32__
MinGW-w64 64bit __MINGW64__
Checking compiler version
gcc
__GNUC__ (e.g. 5) and __GNUC_MINOR__ (e.g. 1).
To check that this is gcc compiler version 5.1 or greater:
#if defined(__GNUC__) && (__GNUC___ > 5 || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1))
// this is gcc 5.1 or greater
#endif
Notice the chack has to be: major > 5 || (major == 5 && minor >= 1). If you only do major == 5 && minor >= 1, it won’t work for version 6.0.
clang
__clang_major__, __clang_minor__, __clang_patchlevel__
Visual Studio
_MSC_VER and _MSC_FULL_VER:
VS _MSC_VER _MSC_FULL_VER
1 800
3 900
4 1000
4 1020
5 1100
6 1200
6 SP6 1200 12008804
7 1300 13009466
7.1 (2003) 1310 13103077
8 (2005) 1400 140050727
9 (2008) 1500 150021022
9 SP1 1500 150030729
10 (2010) 1600 160030319
10 (2010) SP1 1600 160040219
11 (2012) 1700 170050727
12 (2013) 1800 180021005
14 (2015) 1900 190023026
14 (2015 Update 1) 1900 190023506
14 (2015 Update 2) 1900 190023918
14 (2015 Update 3) 1900 190024210
15 (2017 Update 1 & 2) 1910 191025017
15 (2017 Update 3 & 4) 1911
15 (2017 Update 5) 1912
More information:
MinGW
MinGW (aka MinGW32) and MinGW-w64 32bit: __MINGW32_MAJOR_VERSION and __MINGW32_MINOR_VERSION
MinGW-w64 64bit: __MINGW64_VERSION_MAJOR and __MINGW64_VERSION_MINOR
Checking processor architecture
gcc
The meaning of those should be self-evident:
__i386____x86_64____arm__. If defined, you can further check:
__ARM_ARCH_5T____ARM_ARCH_7A__
__powerpc64____aarch64__