VC ++ predefined macro)

In order to facilitate your query, I Will repost a copy from msdn here.

From: msdn.microsoft.com/en-us/library/b0084kay (vs.80). aspx

C/C ++ Preprocessor reference

Predefined macros

Names the predefined ansi c and Microsoft C ++ implementation macros.

The compiler recognizes predefined ansi c macros and the Microsoft C ++ implementation provides several more. these macros take no arguments and cannot be redefined. some of the predefined macros listed below are defined with multiple values. see the following
Tables for more information.

ANSI-compliant predefined macros

Macro	Description
_ Date __	The compilation date of the current source file. The date is a string literal OF THE FORM Mmm dd yyyy. The month nameMmmIs the same as for dates generated by the Library Function AsctimeDeclared in time. h.
_ File __	The name of the current source file._ File __Expands to a string surrounded by double quotation marks. To ensure that the full path to the file is displayed, use /FC (full path of source code file in diagnostics ). You can create your own wide string version_ File __As follows: #include <stdio.h>#define WIDEN2(x) L ## x#define WIDEN(x) WIDEN2(x)#define __WFILE__ WIDEN(__FILE__)wchar_t *pwsz = __WFILE__;int main() {}
_ Line __	The line number in the current source file. The line number is a decimal integer constant. It can be altered with # LineDirective.
_ Stdc __	Indicates full conformance with the ansi c standard. defined as the integer constant 1 only if /Za compiler option is given and you are not compiling C ++ code; otherwise is undefined.
_ Time __	The most recent compilation Time of the current source file. The time is a string literal OF THE FORM Hh: mm: SS.
_ Timestamp __	The date and time of the last modification of the current source file, expressed as a string literal in the form Ddd Mmm date hh: mm: SS yyyy, WhereDddIs the abbreviated day of the week and DateIs an integer from 1 to 31.

Microsoft-specific predefined macros

Macro	Description
_ Atl_ver	Defines the ATL version.
_ Char_unsigned	DefaultCharType is unsigned. defined when /J is specified.
_ Clr_ver	Defines the version of the Common Language Runtime used when the application was compiled. The value returned will be in the following format: Mmmbbbbb Where, M is the major version of the runtime. Mm is the minor version of the runtime. Bbbbb is the build number. // clr_ver.cpp// compile with: /clrusing namespace System;int main() { Console::WriteLine(__CLR_VER);}
_ Cplusplus_cli	Defined when compiling/CLR,/CLR: pure, Or /CLR: safe. Value of _ cplusplus_cli is 200406. _ cplusplus_cli is in effect throughout the Translation Unit. // cplusplus_cli.cpp// compile with: /clr#include "stdio.h"int main() { #ifdef __cplusplus_cli printf("%d\n", __cplusplus_cli); #else printf("not defined\n"); #endif}
_ Counter __	Expands to an integer starting with 0 and incrementing by 1 every time it is used in a compiland. _ Counter __Remembers its state when using precompiled headers. If the last _ Counter __Value was 4 after building a precompiled header (PCH), it will start with 5 on each PCH use. _ Counter __Lets you generate unique variable names. You can use token pasting with a prefix to make a unique name. For example: // pre_mac_counter.cpp#include <stdio.h>#define FUNC2(x,y) x##y#define FUNC1(x,y) FUNC2(x,y)#define FUNC(x) FUNC1(x,__COUNTER__)int FUNC(my_unique_prefix);int FUNC(my_unique_prefix);int main() { my_unique_prefix0 = 0; printf_s("\n%d",my_unique_prefix0); my_unique_prefix0++; printf_s("\n%d",my_unique_prefix0);}
_ Cplusplus	Defined for C ++ programs only.
_ Cpplib_ver	Defined if you include any of the C ++ standard library headers; reports which version of the dinkumware header files are present.
_ Cpprtti	Defined for Code Compiled /GR (enable run-time type information ).
_ Cppunwind	Defined for Code Compiled /GX (enable Exception Handling ).
_ Debug	Defined when compiling /LDD,/MDD, And/MTD.
_ DLL	Defined when /MD or/MDD (multithread DLL) is specified.
_ Funcdname __	Valid only within a function and returns the decorated name of the enclosing function (as a string ). _ Funcdname __Is not expanded if you use /EP or /P compiler option.
_ Funcsig __	Valid only within a function and returns the signature of the enclosing function (as a string ). _ Funcsig __Is not expanded if you use /EP or /P compiler option. On a 64-bit operating system, the calling convention is_ CdeclBy default.
_ Function __	Valid only within a function and returns the undecorated name of the enclosing function (as a string ). _ Function __Is not expanded if you use /EP or /P compiler option.
_ Integral_max_bits	Reports the maximum size (in bits) for an integral type. // integral_max_bits.cpp#include <stdio.h>int main() { printf("%d\n", _INTEGRAL_MAX_BITS);}
_ M_alpha	Defined for DEC Alpha platforms (no longer supported ).
_ M_cee	Defined for a compilation that uses any form/CLR(/CLR: oldsyntax, /CLR: safe, For example ).
_ M_cee_pure	Defined for a compilation that uses/CLR: pure.
_ M_cee_safe	Defined for a compilation that uses/CLR: safe.
_ M_ix86	Defined for x86 processors. See Values for _ m_ix86 for more details.
_ M_ia64	Defined for itanium Processor family 64-bit processors.
_ M_ix86_fp	Expands to a value indicating which/ArchCompiler option was used: 0 if/ArchWas not used. 1 If/Arch: SSEWas used. 2 If/Arch: sse2Was used. See/arch (Minimum CPU architecture) for more information.
_ M_mppc	Defined for Power Macintosh platforms (no longer supported ).
_ M_mrx000	Defined for MIPS platforms (no longer supported ).
_ M_ppc	Defined for PowerPC platforms (no longer supported ).
_ M_x64	Defined for x64 processors.
_ Managed	Defined to be 1 when /CLR is specified.
_ Mfc_ver	Defines the MFC version. For example, 0x0700 represents MFC version 7.
_ Msc_extensions	This macro is defined when compiling with /Ze compiler option (the default). Its value, when defined, is 1.
_ Msc_ver	Reports the major and minor versions of the compiler. for example, 1310 for Microsoft Visual C ++. NET 2003. 1310 represents version 13 and a 1.0 point release. the Visual C ++ 2005 compiler version is 1400. TypeCL /?At the command line to see the major and minor versions of your compiler along with the build number.
_ Msvc_runtime_checks	Defined when one of /RTC compiler options is specified.
_ Mt	Defined when /MD or/MDD (multithreaded DLL) or /Mt or/MTD (multithreaded) is specified.
_ Native_wchar_t_defined	Defined when /ZC: wchar_t is used.
_ OpenMP	Defined when compiling with/OpenMP, returns an integer representing the date of the OpenMP specification implemented by Visual C ++. // _OPENMP_dir.cpp// compile with: /openmp #include <stdio.h> int main() { printf("%d\n", _OPENMP);}
_ Vc_nodefaultlib	Defined when/ZLIs used; see/ZL (omit default library name) for more information.
_ Wchar_t_defined	Defined when /ZC: wchar_t is used or if wchar_t is defined in a system header file encoded in your project.
_ Win32	Defined for applications for Win32 and win64. always defined.
_ Win64	Defined for applications for win64.
_ Wp64	Defined when specifying /Wp64.

As shown in following table, the compiler generates a value for the Preprocessor identifiers that reflect the processor option specified.

Values for _ m_ix86

Option in Development Environment	Command-line option	Resulting value
Blend	/GB	_ M_ix86 = 600(Default. Future compilers will emit a different value to reflect the dominant processor .)
Pentium	/G5	_ M_ix86 = 500
Pentium Pro, Pentium II, and Pentium III	/G6	_ M_ix86 = 600
80386	/G3	_ M_ix86 = 300
80486	/G4	_ M_ix86 = 400