Preprocessor Macros

icubaby defines a number of preprocessor macros. They are all used as a means of discovering support for compiler and standard library features or for simplifying their use in a backwards-compatible fashion. In general, preprocessor macros are avoided if there is a way to implement the behavior within the C++ language itself.

ICUBABY_CXX20

ICUBABY_CXX20 has value 1 when compiling with C++ 20 or later and 0 otherwise.

ICUBABY_CPP_LIB_RANGES_DEFINED

Defined as 1 if the standard library’s __cpp_lib_ranges macro is available and 0 otherwise.

ICUBABY_HAVE_RANGES

Tests for the availability of library support for C++ 20 ranges.

ICUBABY_CPP_CONCEPTS_DEFINED

Defined as true if compiler and library support for concepts are available.

ICUBABY_CPP_LIB_CONCEPTS_DEFINED

Defined as 1 if the standard library’s __cpp_lib_concepts macro is available and 0 otherwise.

ICUBABY_HAVE_CONCEPTS

A macro that evaluates true if the compiler and library have support for C++ 20 concepts.

ICUBABY_REQUIRES(x)

Defined as requires x if C++ 20 concepts are supported and as nothing otherwise.

ICUBABY_CONCEPT_OUTPUT_ITERATOR(x)

Defined as std::output_iterator<x> if C++ 20 concepts are supported and as typename otherwise.

Used as a shortcut to restrict a specific template argument to be an output iterator in C++ 20 and simply declaring a typename in C++ 17.

ICUBABY_CONCEPT_UNICODE_CHAR_TYPE

A convenience macro for defining a template argument that must be icubaby::unicode_char_type.

ICUBABY_NO_UNIQUE_ADDRESS

Defined as [[no_unique_address]] if the attribute is supported and as nothing otherwise.