Predefined Macros

The compiler predefines certain global identifiers, known as manifest constants. Most global identifiers begin and end with two underscores (__).

Note: For readability, underscores are often separated by a single blank space. In your source code, you should never insert whitespace between underscores.

Macro	Value	Description
__BCOPT__	1	Defined in any compiler that has an optimizer.
__BCPLUSPLUS__	0x0570 for BDS 2006 0x0590 for C++Builder 2007 0x0591 for update 1 to C++Builder 2007 0x0592 for RAD Studio 2007 0x0593 for the December update to RAD Studio 2007	Defined if you've selected C++ compilation; will increase in later releases.
__BORLANDC__	0x0570 for BDS 2006 0x0590 for C++Builder 2007 0x0591 for update 1 to C++Builder 2007 0x0592 for RAD Studio 2007 0x0593 for the December update to RAD Studio 2007	Version number.
__CDECL__	1	Defined if Calling Convention is set to cdecl; otherwise undefined.
_CHAR_UNSIGNED	1	Defined by default indicating that the default char is unsigned char. Use the -K compiler option to undefine this macro.
__CODEGUARD__		Defined whenever one of the CodeGuard compiler options is used; otherwise it is undefined.
__CONSOLE__	1	When defined, the macro indicates that the program is a console application.
_CPPUNWIND	1	Enable stack unwinding. This is true by default; use -xd-!ALink(OSCGExceptions1) to disable.
__cplusplus	1	Defined if in C++ mode; otherwise, undefined.
__DATE__	String literal	Date when processing began on the current file.
__DLL__	1	Defined whenever the -WD compiler option is used; otherwise it is undefined.
__FILE__	String literal	Name of the current file being processed.
__FLAT__	1	Defined when compiling in 32-bit flat memory model.
__FUNC__	String literal	Name of the current function being processed. More details.
__LINE__	Decimal constant	Number of the current source file line being processed.
_M_IX86	0x12c	Always defined. The default value is 300. You can change the value to 400 or 500 by using the /4 or /5 compiler options.
__MT__	1	Defined only if the -tWM option is used. It specifies that the multithread library is to be linked.
__PASCAL__	1	Defined if Calling Convention is set to Pascal; otherwise undefined.
__STDC__	1	Defined if you compile with the -A compiler option; otherwise, it is undefined.
__TCPLUSPLUS__	0x0570	Version number.
__TEMPLATES__	1	Defined as 1 for C++ files (meaning that templates are supported); otherwise, it is undefined.
__TIME__	String literal	Time when processing began on the current file.
__TLS__	1	Thread Local Storage. Always true.
__TURBOC__	0x0570 for BDS 2006 0x0590 for C++Builder 2007 0x0591 for update 1 to C++Builder 2007 0x0592 for RAD Studio 2007 0x0593 for the December update to RAD Studio 2007	Will increase in later releases.
_WCHAR_T		Defined only for C++ programs to indicate that wchar_t is an intrinsically defined data type.
_WCHAR_T_DEFINED		Defined only for C++ programs to indicate that wchar_t is an intrinsically defined data type.
_Windows		Defined when compiling on the Windows platform.
__WIN32__	1	Defined for console and GUI applications on the Windows platform.
__linux__		Defined when compiling on the Linux platform.

Note: __DATE__

, __FILE__ , __FUNC__, __LINE__, __STDC__, and __TIME__ cannot be redefined or undefined.