Predefined preprocessor names

When the C/C++ compiler is used for compilation in the SDF environment (COMPILE, CHECK-SYNTAX, and PREPROCESS statements), some preprocessor macros and assertions are predefined, depending on which language mode is selected and which additional options are specified.

For a few macros the value is fixed. It cannot be changed, neither on the command line nor in the source (via #define or #undef). These macros are: __cplusplus, __STDC__, __STDC_VERSION__ and __SNI__STDCplusplus.

Predefined preprocessor macros (defines)

The options specified below are all part of the MODIFY-SOURCE-PROPERTIES statement:

_BOOL	In the language modes C++ V3, C++ 2017 and C++ 2020 with the option KEYWORD-BOOL=*YES
__CGLOBALS_PRAGMA	Always set
__cplusplus	In all C++ language modes: == 1 in Cfront C++ mode == 2 in extended C++ V3 mode == 199612L in strict C++ V3 mode == 201703L in C++ 2017 mode == 202002L in C++ 2020 mode
c_plusplus	In all C++ language modes
__cpp_...	Several defines specified in the C++ standard. They are set when the corresponding feature is supported in the current language mode.
__CFRONT_V3	In language mode Cfront C++
__EDG_NO_IMPLICIT_INCLUSION
	In the modes C++ V3, C++ 2017 and C++ 2020, if implicit inclusion has been disabled with the option IMPLICIT-INCLUDE=*NO within the framework of template instantiation
__EXISTCGLOB	Always set
__HALF_TAG_LOOKUP	Always set
_IEEE	Option FP-ARITHMETICS=*IEEE in MODIFY-MODULE-PROPERTIES statement
LANGUAGE_C	Always set
_LANGUAGE_C	Always set
_LIBCPP_STD_VER	In mode C++ 2020: the compiler will set it to the value 17 In mode C++ 2017: the library headers will set it to the value 17
__LITERAL_ENCODING_ASCII
	Option LITERAL-ENCODING=*ASCII[-FULL]
__LITERAL_ENCODING_EBCDIC
	Option LITERAL-ENCODING=*EBCDIC[-FULL]/*NATIVE
_LONGLONG	Option LONGLONG=*YES
__OLD_SPECIALIZATION_SYNTAX
	== 1 with the option SPECIALIZATION=*OLD
__SHORT_NAMES	Is defined, if C-NAMES=*SHORT is specified
__SIGNED_CHARS__	Option SIGNED-CHARACTER=*YES
__SMALL_VA_DCL	Always set
__SNI	In all C modes and in Cfront C++ mode
__SNI_HOST_BS2000	Always set
__SNI_HOST_BS2000_POSIX	Never set (reserved for compilation in POSIX)
__SNI_PRINTF_CHECK	Always set
__SNI__STDCplusplus	in all C++ language modes: == 0 in extended language modes (STRICT=*NO) == 1 strict language modes (STRICT=*YES)
__SNI_TARG_BS2000	Always set
__SNI_TARG_BS2000_POSIX	Never set (reserved for compilation in POSIX)
__STDC__	Always set: == 0 in extended language modes (STRICT=*NO) == 1 in strict language modes (STRICT=*YES)
__STDC_HOSTED__	Always set
__STDC_NO_ATOMICS__	Always set
__STDC_NO_COMPLEX__	Always set
__STDC_NO_THREADS__	Always set
__STDCPP_DEFAULT_NEW_ALIGNMENT__
	Always set == 8U
__STDC_UTF_16__	Always set
__STDC_UTF_32__	Always set
__STDC_VERS_CRTE__	Undefined in K&R C mode == 199409L in language modes C89, Cfront C++ and C++ V3 == 201112L in language modes C11, C++ 2017 and C++ 2020
__STDC_VERSION__	Undefined in K&R C mode == 199409L in language mode C89 and in all C++ language modes == 201112L in language mode C11
_STRICT_STDC	in strict language modes (STRICT=*YES)
_WCHAR_T	Option KEYWORD-WCHAR=*YES (default in den language modes C++ V3, C++ 2017 and C++ 2020) If this option is not set (e.g. in C modes or in Cfront C++ mode), _WCHAR_T is defined in various standard headers to issue a typedef for wchar_t.
_WCHAR_T_KEYWORD	Option KEYWORD-WCHAR=*YES (default in language modes C++ V3, C++ 2017 and C++ 2020)

Predefined preprocessor assertions (#assert)

The options specified below are all part of the MODIFY-SOURCE-PROPERTIES statement:

data_model(bit32)	Always set
cpu(7500)	On generating /390 code
machine(7500)	On generating /390 code
system(bs2000)	Always set