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#  Library feature-test macros  (since C++20)

From cppreference.com

< [ cpp ](/w/cpp "cpp") ‎ | [ utility ](/w/cpp/utility "cpp/utility")

[ C++ ](/w/cpp "cpp")

[ Compiler support ](/w/cpp/compiler_support "cpp/compiler support")  
---  
[ Freestanding and hosted ](/w/cpp/freestanding "cpp/freestanding")  
[ Language ](/w/cpp/language "cpp/language")  
[ Standard library ](/w/cpp/standard_library "cpp/standard library")  
[ Standard library headers ](/w/cpp/header "cpp/header")  
[ Named requirements ](/w/cpp/named_req "cpp/named req")  
[ Feature test macros ](/w/cpp/feature_test "cpp/feature test") (C++20)  
[ Language support library ](/w/cpp/utility#Language_support "cpp/utility")  
[ Concepts library ](/w/cpp/concepts "cpp/concepts") (C++20)  
[ Metaprogramming library ](/w/cpp/meta "cpp/meta") (C++11)  
[ Diagnostics library ](/w/cpp/error "cpp/error")  
[ General utilities library ](/w/cpp/utility "cpp/utility")  
[ Strings library ](/w/cpp/string "cpp/string")  
[ Containers library ](/w/cpp/container "cpp/container")  
[ Iterators library ](/w/cpp/iterator "cpp/iterator")  
[ Ranges library ](/w/cpp/ranges "cpp/ranges") (C++20)  
[ Algorithms library ](/w/cpp/algorithm "cpp/algorithm")  
[ Numerics library ](/w/cpp/numeric "cpp/numeric")  
[ Localizations library ](/w/cpp/locale "cpp/locale")  
[ Input/output library ](/w/cpp/io "cpp/io")  
[ Filesystem library ](/w/cpp/filesystem "cpp/filesystem") (C++17)  
[ Regular expressions library ](/w/cpp/regex "cpp/regex") (C++11)  
[ Concurrency support library ](/w/cpp/thread "cpp/thread") (C++11)  
[ Technical specifications ](/w/cpp/experimental "cpp/experimental")  
[ Symbols index ](/w/cpp/symbol_index "cpp/symbol index")  
[ External libraries ](/w/cpp/links/libs "cpp/links/libs")  
  
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[ Utilities library ](/w/cpp/utility "cpp/utility")

|  [ Language support ](/w/cpp/utility#Language_support "cpp/utility")  
---  
[ Type support ](/w/cpp/types "cpp/types") (basic types, RTTI)  
**Library feature-test macros** (C++20)  
[ Dynamic memory management ](/w/cpp/memory "cpp/memory")  
[ Program utilities ](/w/cpp/utility/program "cpp/utility/program")  
[ Coroutine support ](/w/cpp/coroutine "cpp/coroutine") (C++20)  
[ Variadic functions ](/w/cpp/utility/variadic "cpp/utility/variadic")  
[ is_constant_evaluated  ](/w/cpp/types/is_constant_evaluated "cpp/types/is
constant evaluated") (C++20)  
[ is_within_lifetime  ](/w/cpp/types/is_within_lifetime "cpp/types/is within
lifetime") (C++26)  
[ initializer_list  ](/w/cpp/utility/initializer_list "cpp/utility/initializer
list") (C++11)  
[ source_location  ](/w/cpp/utility/source_location "cpp/utility/source
location") (C++20)  
[ Debugging support ](/w/cpp/utility#Debugging_support "cpp/utility")  
[ is_debugger_present  ](/w/cpp/utility/is_debugger_present "cpp/utility/is
debugger present") (C++26)  
[ breakpoint_if_debugging  ](/w/cpp/utility/breakpoint_if_debugging
"cpp/utility/breakpoint if debugging") (C++26)  
[ breakpoint  ](/w/cpp/utility/breakpoint "cpp/utility/breakpoint") (C++26)  
[ Three-way comparison ](/w/cpp/utility#Three-way_comparison "cpp/utility")  
[ three_way_comparable  three_way_