computer programming important component standard library standard library provides data structures list set commonly referred containers common trait containers ability change size execution program achieve form dynamic memory allocation usually required handle requests allocation memory given container standard library provides general purpose default custom supplied programmer invented originally intended means library flexible independent underlying memory model allowing programmers utilize custom reference types library process adopting standard committee realized complete memory model unacceptable performance penalties remedy requirements restrictive result level provided limited originally envisioned scenarios desirable common reasons writing custom include improving performance memory pools access different types memory like shared memory garbage collected memory particular programs frequent small amounts memory benefit greatly specialized terms running time memory background presented standard template library standards committee march library received preliminary approval issues raised particular requested library containers independent underlying memory model led creation consequently container rewritten accept adapting included standard library worked closely members standards committee including observed custom potentially implement persistent storage containers time considered important interesting insight original proposal incorporated language features accepted committee ability use template arguments features compiled existing according enormous demand andy time trying verify non implemented features correctly library previously reference types directly refer types defined later described follows nice feature place mentions machine related types roughly lines code originally intended completely memory model standards committee realized approach lead unacceptable efficiency remedy additional wording added requirements particular container assume type definitions related integral types equivalent provided default instances given type compare equal effectively original design goals limiting carry state later commented bad idea theory work practice observed useful change core language regards references necessary revision standard removed words requiring given type compare equal use normal changes useful allow manage process shared memory current purpose programmer control memory allocation containers adapt address model underlying hardware fact revised standard eliminated ability represent extensions address model formally deliberately eliminating original purpose requirements class requirements particular class capable memory object type provide types reference reference value type declaring objects references objects type provide type size type unsigned type represent largest size object allocation model defined similarly signed integral difference type represent difference allocation model standard library implementation allowed assume simply library encouraged support general objects type member function signature size type void hint function returns element newly allocated array large contain objects type memory allocated objects constructed optional argument points object allocated hint implementation new memory allocated order improve locality implementation free ignore argument corresponding void size type member function accepts returned previous invocation member function number elements max size member function returns largest number objects type expected successfully allocated invocation value returned typically size type address member function returns denoting address object given reference object construction destruction performed separately allocation required member functions construct destroy handles object construction destruction respectively functions equivalent following code uses placement new calls directly copy objects type constructed objects type region memory compares equal required supply template class member template enables possibility obtaining related terms different type example given type objects type related type objects type long obtained long custom main reasons writing custom performance utilizing specialized custom substantially improve performance memory usage program default uses operator new memory implemented thin layer allocation functions usually allocation large memory blocks approach work containers large memory like containers require frequent small objects map list default generally slow common problems based include poor locality reference excessive memory popular approach improve performance create memory pool based instead memory time item inserted removed container large block memory memory pool allocated possibly program custom serve individual allocation requests simply returning memory pool actual memory deferred lifetime memory pool ends example memory pool based found viable use custom memory related errors achieved writing extra memory places information ensure memory allocated type provide limited protection subject custom treated experts authors including effective modern design requires instances equivalent notes effect forces portable state standard encourage library support calls relevant lovely sentiment offers restriction programming language hand argues apparently restriction object information particularly pointing need state better performance mentions use cases custom memory pool shared memory garbage collected memory presents implementation uses internal memory pool fast allocation small memory notes performed provided implementation usage standard containers specified template argument like class standard library containers different arguments distinct types function expecting argument accept default enhancements standard enhanced interface allow containers memory strings map lists sets user defined types ensure memory sourced container example
Allocator (C++)