;,C IS ! MO/ 9FLU5TIAL PROGRAMM+
LANGUAGE "E CR1T$4 ,DESIGN$ BY ,D5NIS
,RIT*IE AT ,BELL ,LABS 2T #AIFI & #AIGC
Z ! IMPLE;TA;N LANGUAGE = ! ,UNIX OP]AT+
SY/EM1 X O3UPIES A POSI;N 9 COMPUT+ T NO
O!R LANGUAGE HAS MAT*$3 NE>LY E OP]AT+
SY/EM K]NEL 9 PRODUC;N  ,L9UX1 ,W9D[S1
MAC,O,S1 I,O,S1 ,&ROID'S L[] LAY]S1 !
,B,S,DS1 & MO/ EMB$D$ FIRMW>E  IS WRITT5
PRIM>ILY 9 ;,C4 ,NE>LY E LANGUAGE CR1T$
S9CE #AIHJ EI COMPILES TO ;,C1 0
IMPLE;T$ 9 ;,C1 BORR[S ,C'S SYNTAX1 OR
DEF9ES XF 9 OPPOSI;N TO ;,C4 ,!
SEMICOLONS1 ! CURLY BRACES1 ! = LOOPS1 !
IF_/ELSE BLOCKS1 ! PR9TF =MAT /R+S  ^!
>E N F1TURES ( 8;,C-L LANGUAGES40 ,!Y >E
F1TURES ( ;,C T ! RE/ ( ! _W ADOPT$4
;,C IS FIFTY-F\R YE>S OLD4 ,X IS / !
SECOND MO/ US$ PROGRAMM+ LANGUAGE ON
,E>? "<2H ,PY?ON1 DEP5D+ ON ! 9DEX"> & !
F/ *OICE = ANY S(TW>E T M/ TALK DIRECTLY
TO H>DW>E4 ,X HAS BE5 /&>DIZ$ FIVE "TS 
,C#HI1 ,C#II1 ,C#AA1 ,C#AG1 & ,C#BC  & !
COMMITTEE IS ALR "W+ ON ,C#B;Y1 ! NEXT
REVI.N4 ,! LANGUAGE T ,RIT*IE BUILT ON A
,,PDP-#AA 9 A ,NEW ,J]SEY (FICE IS / !
LANGUAGE ! _W RUNS ON4
,! ,,TIOBE ,9DEX1 ,/ACK ,OV]FL[ SURVEYS1
& ,GIT,HUB USAGE /ATI/ICS ALL PLACE ;,C
9 ! TOP FIVE LANGUAGES YE> AF YE>4 ,X
RANKS F/ OR SECOND AM;G LANGUAGES T %IP
PRODUCTS P DEP5D ON )\T "K+ X  ! FIRMW>E
9 _! C>1 ! K]NEL ( _! PH"O1 ! DATABASE
2H _! BANK4 ;,C IS ! 9VISIBLE
9FRA/RUCTURE ( MOD]N CIVILIZA;N4
,2F ;,C3 ! ANCE/RY
;,C DID N EM]GE F NO?+4 ,XS FAMILY TREE
RUNS "? ?REE LANGUAGES1 EA* /RIPP+ AWAY
A LAY] ( AB/RAC;N3
,,BCPL "<#AIFG">  ,M>T9 ,RI*>DS DESIGN$
,,BCPL "<,BASIC ,COMB9$ ,PROGRAMM+
,LANGUAGE"> AT ,CAMBRIDGE4 ,X 0 TYPE.S3
"EY?+ 0 A MA*9E ^W4 ,X 9TRODUC$ ! _/_/
COM;T "<: ;,C DROPP$ & ,C#II BR"\ BACK
?IRTY YE>S LAT]"> & ! IDEA T A SY/EMS
LANGUAGE %D COMPILE TO E6ICI5T CODE & 2
CLOSE TO ! MA*9E4
;,B "<#AIFI">  ,K5 ,?OMPSON1 "W+ ON ! F/
,UNIX ON ! ,,PDP-#G AT ,BELL ,LABS1 NE$$
"S?+ HI<]-LEVEL ?AN ASSEMBLY B L1N] ?AN
! FULL ,,=TRAN COMPIL] HE TRI$ & AB&ON$
AF "O "D4 ,HE WROTE ;,B1 D]IV$ F ,,BCPL
& 9FLU;ED BY ,?OMPSON'S [N E>LI]
LANGUAGE ,BON4 ;,B 0 AL TYPE.S  E VALUE
0 A ^W4 ,X "W$ ON ! ^W-ORI5T$ ,,PDP-#G1
B :5 ,UNIX MOV$ TO ! BYTE-ORI5T$
,,PDP-#AA1 ! LACK ( TYPES 2CAME A
CRITICAL PROBLEM4 ,Y CD N EXPRESS A "*1
A BYTE1 OR A PO9T] TO A BYTE 9 A
LANGUAGE ": "EY?+ 0 A ^W4
,,NB _/ E>LY ;,C "<#AIGA#AIGB">  ,RIT*IE
2GAN ADD+ A TYPE SY/EM TO ;,B4 ,= A :ILE
! RESULT 0 CALL$ 8,,NB0 "<,NEW ;,B">4 ,!
TYPE SY/EM GREW  *>1 9T1 PO9T]S1 >RAYS1
/RUCTURES  & AT "S PO9T ,,NB 2CAME ;,C4
,! "N IS SIMPLY ! NEXT LR AF ;,B1 ?\<
,RIT*IE NOT$ ) "*I/IC "U/ATE;T T ! NAM+
0 "PLY CO9CID;E & "PLY SEQU;E4 ,!
TRANSI;N 0 N A CL1N BR1K3 E>LY ;,C
RETA9$ ,B'S OP]ATOR SYNTAX "<! "6"6 & --
OP]ATORS1 ! COMB9$ ASSIGN;T OP]ATORS
"6"71 -"71 ! T]N>Y 83">1 XS T]SE V>IABLE
NAM+ 3V5;NS1 & XS FUNDA;TAL ORI5TA;N
T[>D ! MA*9E4 ;,C ADD$ TYPES ON TOP (
,B'S EXI/+ VOCABUL>Y R ?AN DESIGN+ A NEW
LANGUAGE F SCRAT*  : IS :Y ,C'S TYPE
SY/EM HAS ALW FELT ?9 COMP>$ TO
LANGUAGES DESIGN$ ) TYPES Z A F/
PR9CIPLE4
,! RESULT 0 A LANGUAGE T SAT PRECISELY 9
! GAP 2T ASSEMBLY & ! 8HI<-LEVEL0
LANGUAGES ( ! ]A4 ;,C GAVE Y TYPES1
/RUCTURES1 FUNC;NS1 & A /&>D LIBR>Y  B X
AL GAVE Y PO9T]S1 PO9T] >I?METIC1 BIT
MANIPULA;N1 & ! ABIL;Y TO CA/ ANY?+ TO
ANY?+4 ,? DELIB]ATE POSI;N+  CLOSE 5 TO
! MA*9E TO REPLACE ASSEMBLY1 AB/RACT 5
TO 2 PORTABLE  IS ,C'S DEF9+ DESIGN
*OICE & ! R1SON = BO? XS SU3ESS & XS
PROBLEMS4
8;,C CAME 9TO 2+ 9 ! YE>S #AIFI#AIGC1 9
P>ALLEL ) ! E>LY DEVELOP;T ( ! ,UNIX
OP]AT+ SY/EM2 ! MO/ CR1TIVE P]IOD O3URR$
DUR+ #AIGB40  ,D5NIS ,RIT*IE1 8,!
,DEVELOP;T ( ! ;,C ,LANGUAGE10 #AIIC
,! BIR?3 ,BELL ,LABS & ,UNIX
.<FIGURE3 ,K5 ,?OMPSON "<LEFT"> & ,D5NIS
,RIT*IE AT A ,,PDP-#AA1 CIRCA #AIGC4
,PUBLIC DOMA94.>
,! CRITICAL MO;T CAME 9 ! SUMM] ( #AIGC4
,?OMPSON _H TRI$ TO REWRITE ,UNIX 9 ;,C
! PREVI\S SUMM] B GAVE UP  ! LANGUAGE
LACK$ /RUCTURES1 & ! G5]AT$ CODE 0 N
E6ICI5T 5\<4 ,OV] ! 9T]V5+ YE>1 ,RIT*IE
ADD$ /RUCT1 IMPROV$ ! COMPIL]'S CODE
G5]A;N1 & SOLV$ 5 ( ! REMA9+ PROBLEMS T
A SECOND ATTEMPT SU3E$$4 ,BY ! 5D (
#AIGC1 ! ,UNIX K]NEL 0 WRITT5 9 ;,C4
,? 0 REVOLU;N>Y4 ,OP]AT+ SY/EMS _H ALW
BE5 WRITT5 9 ASSEMBLY  EA* "O TI$ TO XS
SPECIFIC H>DW>E4 ,A K]NEL WRITT5 9 A
HI<-LEVEL LANGUAGE CD1 9 PR9CIPLE1 2
PORT$ TO DI6]5T MA*9ES BY REWRIT+ ONLY A
SMALL H>DW>E-DEP5D5T LAY]4 ,:5 ,UNIX 0
PORT$ TO ! ,9T]DATA #H_/#CB 9 #AIGH1 T
PR9CIPLE 2CAME FACT4 ,UNIX  & "!=E ;,C 
2GAN SPR1D+ TO E >*ITECTURE T EXI/$4
,! SYMBIOSIS 2T ;,C & ,UNIX _C 2
OV]/AT$4 ;,C 0 DESIGN$ TO WRITE ,UNIX4
,UNIX 0 DESIGN$ TO 2 WRITT5 9 ;,C4 ,!
,UNIX PHILOSOPHY  SMALL TOOLS T COMPOSE1
TEXT Z A UNIV]SAL 9T]FACE1 ! FILE SY/EM
Z A "NSPACE  %AP$ ,C'S /&>D LIBR>Y4 ,!
/DIO4H FUNC;NS "<FOP51 FR1D1 FPR9TF1
FCLOSE"> >E A DIRECT REFLEC;N ( ,UNIX'S
FILE ,I_/,O MODEL4 ,! MA9"<>GC1 >GV">
3V5;N MIRRORS ,UNIX'S PROCESS MODEL4 ,!
5TIRE ;,C ECOSY/EM ASSUMES A ,UNIX-L
5VIRON;T1 : IS :Y ,C'S 9FLU;E SPR1D
EXACTLY Z F> Z ,UNIX DID  : IS TO SAY1
"EY":4
,! ,UNIX S\RCE CODE LIC5SE F ,,AT@&,T1
4TRIBUT$ TO UNIV]SITIES />T+ 9 #AIGE1 0
"O ( ! MO/ 3SEQU5TIAL LIC5S+ DECI.NS 9
COMPUT+ HI/ORY4 ,X PUT ;,C & ,UNIX 9TO !
H&S ( ?\S&S ( COMPUT] SCI;E /UD5TS1 :O
LE>N$ BO? SIMULTANE\SLY & C>RI$ !M 9TO
9DU/RY4 ,B]KELEY'S MODIFICA;NS "<,,BSD">
L$ TO ,FREE,B,S,D1 ,OP5,B,S,D1
,NET,B,S,D1 & EV5TUALLY MAC,O,S & I,O,S4
,! ACADEMIC ,UNIX DIASPORA MADE ;,C !
DEFAULT LANGUAGE ( SY/EMS PROGRAMM+
_WWIDE4
,K@&,R3 ! :ITE BOOK
,9 #AIGH1 ,BRIAN ,K]NI<AN & ,D5NIS
,RIT*IE PUBLI%$ ,! ;,C ,PROGRAMM+
,LANGUAGE  UNIV]SALLY "KN Z ,K@&,R OR 8!
:ITE BOOK40 ,X S]V$ Z ! DE FACTO /&>D =
;,C = OV] A DECADE1 UNTIL ,,ANSI /&>DIZ$
! LANGUAGE 9 #AIHI4
,K@&,R IS WIDELY REG>D$ Z "O ( ! BE/
PROGRAMM+ BOOKS "E WRITT54 ,XS 3CISE;S1
CL>;Y1 & TRU/ 9 ! R1D] SET A /&>D T FEW
TE*NICAL BOOKS H MAT*$4 ,! FAM\S F/
PROGRAM3
_?9CLUDE @</DIO4H@>
MA9"<"> _<     PR9TF"<8HELLO1 _W_*N0">2
_>
APPE>$ ON PAGE #F & 2CAME ! UNIV]SAL F/
PROGRAM 9 E LANGUAGE TUTORIAL S9CE4 ,!
8HELLO1 _W0 TRADI;N IS ,K@&,R'S MO/
VISIBLE CULTURAL 3TRIBU;N1 B ! BOOK'S
R1L A*IEVE;T 0 DEMON/RAT+ T A SY/EMS
LANGUAGE CD 2 EXPLA9$ CLE>LY 9 #BBH
PAGES4
,K@&,R ;,C _H NO =MAL /&>D4 ,! BOOK 0 !
/&>D  :AT ,RIT*IE & ,K]NI<AN SD !
LANGUAGE DID1 T IS :AT ! LANGUAGE DID4
,COMPIL]S T 4AGRE$ 7 3SID]$ WR;G4 ,? "W$
REM>KABLY WELL = A DECADE1 B Z ;,C SPR1D
TO NON-,UNIX PLAT=MS "<,,MS-,,DOS1
,,VMS1 MA9FRAMES">1 ! DIV]G;ES
A3UMULAT$4 ,V5DORS ADD$ _! [N EXT5.NS 
F> & NE> PO9T]S ON ,,MS-,,DOS = SEG;T$
MEMORY1 _?PRAGMA DIRECTIVES =
PLAT=M-SPECIFIC 2HAVIOR1 NON-/&>D LIBR>Y
FUNC;NS  & BY ! MID-#AIHJ;S1 ! IDEA T
8;,C IS PORTABLE0 0 2COM+ M ASPIRA;N ?AN
FACT4 ,! NE$ = A =MAL /&>D 0 OBVI\S4
,! ,K@&,R ]A AL E/ABLI%$ ! PRACTICE ( !
COMPIL] Z A REF];E IMPLE;TA;N4 ,:5 !
BOOK 0 AMBIGU\S  & X "S"TS 0  PROGRAMM]S
LOOK$ AT :AT ,RIT*IE'S COMPIL] DID4 ,!
,,PDP-#AA COMPIL]'S 2HAVIOR 2CAME ! DE
FACTO DEF9I;N ( $GE CASES4 ,? PRACTICE
P]SI/$ WELL 9TO ! ,,ANSI ]A3 :5 ! /&>D
SAYS "O ?+ & ! COMPIL] DOES ANO!R1 "W+
PROGRAMM]S FOLL[ ! COMPIL]4 ,! T5.N 2T !
AB/RACT /&>D & 3CRETE IMPLE;TA;NS IS "O
( ! RECURR+ !MES ( ,C'S HI/ORY4
,! /&>DS3 ,,ANSI ;,C "? ,C#BC
,C#HI _/ ,C#IJ  ! F.DA;N
,9 #AIHC1 ,,ANSI =M$ COMMITTEE
,X#C;,J#AA TO /&>DIZE ;,C4 ,! RESULT1
PUBLI%$ 9 #AIHI Z ,,ANSI ,X#C4AEI-#AIHI
& ADOPT$ BY ,,ISO 9 #AIIJ Z ,,ISO_/,,IEC
#IHII3#AIIJ1 0 ! F/ =MAL ;,C /&>D4 ,X IS
"KN 9T]*ANG1BLY Z ,C#HI "<! ,,ANSI YE>">
OR ,C#IJ "<! ,,ISO YE>">4
,C#HI CODIFI$ EXI/+ PRACTICE & ADD$
G5U9ELY NEW F1TURES3
,F1TURE  ,:AT X ADD$   VOID  ,AN
EXPLICIT 8NO VALUE0 TYPE  FUNC;NS CD
F9ALLY DCL !Y RETURN$ NO?+   5UM  ,"ND
9TEG] 3/ANTS   3/  ,BORR[$ F ,C"6"6 
R1D-ONLY V>IABLES   VOLATILE  ,= H>DW>E
REGI/]S & SIGNAL H&L]S  TELLS ! COMPIL]
N TO OPTIMIZE AWAY R1DS   SIGN$ _/
UNSIGN$  ,EXPLICIT SIGN$;S   ,FUNC;N
PROTOTYPES  ,AL BORR[$ F ,C"6"6  9T
ADD"<9T A1 9T ;B">2 9/1D ( J 9T ADD"<">2
@</DLIB4H@>1 @</R+4H@>1 @<LIMITS4H@> 
,/&>D LIBR>Y H1D]S ORGANIZ$ 9TO A COH]5T
SET ,C#HI AL =MALIZ$ ! Z-IF RULE  !
COMPIL] MAY TRANS=M ! PROGRAM 9 ANY WAY1
Z L;G Z ! OBS]VABLE 2HAVIOR IS ID5TICAL
TO ! AB/RACT MA*9E'S EXECU;N4 ,? RULE IS
! F.DA;N ( ALL MOD]N ;,C OPTIMIZA;N4
,C#HI IS / ! T>GET ( "S NEW CODE 9
#BJBF4 ,! .<.<,,ALB ;,C BACK5D.>.>
EXPLICITLY G5]ATES ,C#HI  ! OLDE/1 MO/
PORTABLE ;,C DIALECT  2C ,C#HI COMPILES
ON ESS5TIALLY E COMPIL] "E MADE1 F T9Y
EMB$D$ TOOL*A9S TO MOD]N ,,GCC & ,CLANG4
,! DELIB]ATE *OICE ( ,C#HI IS A F1TURE1
N A COMPROMISE4
,C#II  ! MOD]NIZA;N
,PUBLI%$ 9 #AIII1 ,C#II "<,,ISO_/,,IEC
#IHII3#AIII"> 0 ! F/ MAJOR REVI.N 9 A
DECADE4 ,X TRANS=M$ ;,C F A #AIGJ;S
LANGUAGE ) #AIHI =MALIZA;N 9TO "S?+
RECOGNIZABLY MOD]N3
- _/_/ COM;TS  BR"\ BACK F ,,BCPL VIA
,C"6"61 AF ?IRTY YE>S ( _/ _/ ONLY - L;G
L;G 9T  GU>ANTE$ #FD-BIT 9TEG]S -
@</D9T4H@> & @<9TTYPES4H@>  FIX$-WID?
9TEG] TYPES "<9T#CB.-T1 U9T#FD.-T">1 5D+
DECADES ( 8H[ WIDE IS 9T ON ? PLAT=M80 -
.-,BOOL _/ @</DBOOL4H@>  A PROP] BOOL1N
TYPE - RE/RICT  A PO9T] QUALIFI] TELL+ !
COMPIL] T NO O!R PO9T] ALIASES ? "O1
5ABL+ A7RESSIVE OPTIMIZA;N - ,COMP.D
LIT]ALS  "</RUCT PO9T">_<4X "7 #A1 4Y "7
#B_> 9L9E - ,DESIGNAT$ 9ITIALIZ]S 
4FIELD "7 VALUE SYNTAX = /RUCTURES &
>RAYS - ,V>IABLE-L5G? >RAYS "<,V,L,AS"> 
/ACK-ALLOCAT$ >RAYS ^: SIZE IS DET]M9$
AT RUN"T - ,9L9E FUNC;NS  9L9E KEY^W1 F
,C"6"6 - ,MIX$ DECL>A;NS & CODE 
V>IABLES NO L;G] _H TO 2 DECL>$ AT ! TOP
( A BLOCK "<F ,C"6"6"> - @<F5V4H@> 
FLOAT+-PO9T 5VIRON;T 3TROL - SNPR9TF  !
SAFE V].N ( SPR9TF1 PREV5T+ BU6] OV]FL[S
- ,V>IADIC MACROS  _?DEF9E ,,LOG"<FMT1
444"> FPR9TF"</D]R1 FMT1
.-.-,,VA.-,,>GS.-.-"> - .-.-FUNC.-.- 
AUTOMATIC /R+ 3TA9+ ! CURR5T FUNC;N "N
,C#II 0 A G5U9ELY GD /&>D4 ,XS TRAG$Y 0
,MICROS(T3 ,,MSVC DID N FULLY SUPPORT
,C#II = NE>LY TWO DECADES1 : FRACTUR$ !
ECOSY/EM & =C$ _M PROJECTS TO /AY ON
,C#HI = PORTABIL;Y TO ,W9D[S4 ,? CR1T$
AN ABSURD SITUA;N ": ! MO/ POPUL>
DESKTOP OP]AT+ SY/EM'S PRIM>Y COMPIL]
DID N SUPPORT A #AIII LANGUAGE /&>D WELL
9TO ! #BJAJ;S4 ,! 3SEQU;ES RIPPLE "? !
;,C ECOSY/EM TO ? "D  _M WIDELY-US$
LIBR>IES / T>GET ,C#HI OR A ,C#HI_/,C#II
HYBRID 2C !Y _C ASSUME FULL ,C#II
SUPPORT4
,! ,,VLA F1TURE1 9 "PICUL>1 PROV$
DIVISIVE4 ,:ILE 3CEPTUALLY USE;L1
,V,L,AS MADE /ACK USAGE UNPR$ICTABLE & 7
3SID]$ A SECUR;Y RISK "</ACK OV]FL[
ATTACKS">4 ,L9US ,TORVALDS BANN$ ,V,L,AS
F ! ,L9UX K]NEL1 & ! K]NEL T1M SP5T YE>S
ELIM9AT+ !M F ! CODEBASE4 ,C#AA MADE
,V,L,AS OP;NAL1 TACITLY AC"KL$G+ !
3TROV]SY4
,C#AA  3CURR5CY & SAFETY
,PUBLI%$ 9 #BJAA1 ,C#AA "<,,ISO_/,,IEC
#IHII3#BJAA"> ADDRESS$ TWO MAJOR GAPS3
- @<?R1DS4H@>  A /&>D ?R1D+ ,,API "<?R1D
CR1;N1 MUTEXES1 3DI;N V>IABLES">1 F9ALLY
GIV+ ;,C PORTABLE MULTI?R1D+ )\T REQUIR+
,,POSIX - @</DATOMIC4H@>  ATOMIC TYPES &
OP]A;NS1 ESS5TIAL = LOCK-FREE PROGRAMM+
- ,A ?R1D-AW>E MEMORY MODEL  SPECIFY+ H[
?R1DS 9T]ACT ) MEMORY1 9CLUD+
ACQUIRE_/REL1SE SEMANTICS -
.-,/ATIC.-ASS]T  COMPILE-"T ASS];NS -
.-,ALIGNAS _/ .-,ALIGN(  ALIGN;T 3TROL -
,ANONYM\S /RUCTURES & UNIONS  /RUCT _<
/RUCT _< 9T ;X1 ;Y2 _>2 _>2 - @<U*>4H@> 
,UNICODE "* TYPES "<*>#AF.-T1 *>#CB.-T">
- .-,G5]IC  TYPE-G5]IC SELEC;N1 ,C'S
ANSW] TO FUNC;N OV]LOAD+3 .-,G5]IC"<;X1
9T3 89T01 FLOAT3 8FLOAT01 DEFAULT3
8O!R0">
,C#AA AL MADE ,V,L,AS OP;NAL "<!Y _H BE5
M&ATORY 9 ,C#II B POORLY SUPPORT$ ON "S
PLAT=MS">1 9TRODUC$ B.DS-*ECK+ 9T]FACES
9 AN OP;NAL ANNEX "<,ANNEX ;,K">1 &
DEPRECAT$ ! GETS FUNC;N "<: 0 F9ALLY
REMOV$">4
,C#AG  ! CL1NUP
,PUBLI%$ 9 #BJAH1 ,C#AG "<,,ISO_/,,IEC
#IHII3#BJAH"> 0 A 8BUG-FIX0 REL1SE4 ,X
9TRODUC$ NO NEW F1TURES  ONLY DEFECT
RESOLU;NS & CL>IFICA;NS4 ,XS PRIM>Y
VALUE 0 E/ABLI%+ A CL1N1 UNAMBIGU\S
BASEL9E = ! NEXT MAJOR REVI.N4
,C#BC  ! PRES5T
,PUBLI%$ 9 ,OCTOB] #BJBD1 ,C#BC
"<,,ISO_/,,IEC #IHII3#BJBD"> IS ! CURR5T
/&>D & ! MO/ SIGNIFICANT REVI.N S9CE
,C#II4 ,X MOD]NIZES ,C'S SURFACE :ILE
PRES]V+ XS "*3
,TYPES & 3/ANTS3 - NULLPTR & NULLPTR.-T 
A PROP] NULL PO9T] 3/ANT & TYPE - TRUE1
FALSE1 BOOL Z KEY^WS "<NO L;G] MACROS F
@</DBOOL4H@>"> - .-,BIT,9T"<;,N"> 
BIT-PRECISE 9TEG]S ( >BITR>Y WID? -
TYPE( & TYPE(.-UNQUAL  /&>DIZ$ TYPE(
OP]ATOR - 3/EXPR  COMPILE-"T 3/ANTS
,SYNTAX3 - ATTRIBUTE SYNTAX  UNIFI$
ATTRIBUTES "<DEPRECAT$1 FALL"?1 MAYBE
UNUS$1 NODISC>D1 NORETURN"> - _?EMB$ 
EMB$ B9>Y DATA "<FILES1 IMAGES1
FIRMW>E"> DIRECTLY 9TO S\RCE Z 9ITIALIZ]
DATA - _?ELIFDEF _/ _?ELIFNDEF 
PREPROCESSOR %OR?& - .-.-HAS.-9CLUDE 
TE/ = H1D] AVAILABIL;Y -
.-.-,,VA.-,,OPT.-.-  OP;NAL V>IADIC
MACRO >GU;T H&L+ - ,DIGIT SEP>ATOR ' 9
NUM]IC LIT]ALS "<#A'#JJJ'#JJJ"> - ,B9>Y
LIT]AL PREFIX #J;;B "<#J;B#AJAJ">
,LIBR>Y3 - @</DBIT4H@>  BIT MANIPULA;N
FUNC;NS - @</DCKD9T4H@>  *ECK$ 9TEG]
>I?METIC "<CKD.-ADD1 CKD.-SUB1
CKD.-MUL"> - MEMSET.-EXPLICIT  GU>ANTE$
N TO 2 OPTIMIZ$ AWAY "<= Z]O+ SECRETS">
- /RDUP _/ /RNDUP  F9ALLY /&>DIZ$ AF
DECADES Z ,,POSIX EXT5.NS
,& ALR 9 PROGRESS3 ,C#B;Y1 ! NEXT
REVI.N1 ) ! LATE/ DRAFT "<,N#CHHF">
PUBLI%$ 9 ,MAY #BJBF4
,C#BC'S .*_?EMB$.* DIRECTIVE SOLVES A
PROBLEM Z OLD Z ;,C XF3 9CLUD+ B9>Y DATA
9 A PROGRAM4 ,2F .*_?EMB$.*1 ! /&>D
APPROA* 0 .*XXD -I.* TO 3V]T A FILE 9TO
A ;,C >RAY 9ITIALIZ]  A G5]AT$ S\RCE
FILE T CD 2 MILLIONS ( L9ES L;G4
.*_?EMB$.* REPLACES ? ) A S+LE
PREPROCESSOR DIRECTIVE T COMPIL]S C H&LE
9T]NALLY1 DRAMATICALLY IMPROV+ COMPILE
"TS = PROGRAMS T 9CLUDE FIRMW>E IMAGES1
TEXTURE DATA1 OR C]TIFICATE BUNDLES4
,! LANGUAGE XF
,:AT X LOOKS L 9 #BJBF
,MOD]N ;,C1 WRITT5 TO ,C#BC1 IS CL1N]
?AN MO/ P EXPECT3
_?9CLUDE @</DIO4H@> _?9CLUDE @</DLIB4H@>
_?9CLUDE @</DBIT4H@>
.<.<NODISC>D.>.> /ATIC 9T
POPC.T.-&.-*ECK"<UNSIGN$ ;N"> _<     9T
BITS "7 /DC.-C.T.-"OS"<;N">2     IF
"<BITS "7"7 #J"> RETURN -#A2     RETURN
BITS2 _>
9T MA9"<VOID"> _<     3/EXPR UNSIGN$
MAGIC "7 #JX,D,E,A,D',,BEEF2     9T BITS
"7 POPC.T.-&.-*ECK"<MAGIC">2    
PR9TF"<8#JX.0,X HAS .0D SET BITS_*N01
MAGIC1 BITS">2
_/_/ ,C#BC3 TYPE( 9F];E    
TYPE("<MAGIC"> COPY "7 MAGIC2    
PR9TF"<8,COPY3 #JX.0,X_*N01 COPY">2
_/_/ ,C#BC3 NULLPTR 9/1D ( ,,NULL     9T
"9P "7 NULLPTR2     IF "<;P "7"7
NULLPTR"> _<         PR9TF"<8,PO9T] IS
NULL "<N J Z]O">_*N0">2     _> _>
,ATTRIBUTES1 3/EXPR1 DIGIT SEP>ATORS1
NULLPTR1 TYPE(1 @</DBIT4H@>  ,C#BC BR+S
G5U9E QUAL;Y-(-LIFE IMPROVE;TS :ILE
REMA9+ RECOGNIZABLY ;,C4
,! TYPE SY/EM
,C'S TYPE SY/EM IS FAM\SLY M9IMAL4 ,E
VALUE IS ULTIMATELY A SEQU;E ( BYTES4 ,!
FUNDA;TAL TYPES >E3
,TYPE  ,WID? "<TYPICAL">  ,PURPOSE   *> 
#H BITS  ,"*S1 RAW BYTES   %ORT  #AF
BITS  ,SMALL 9TEG]S   9T  #CB BITS  ,!
8NATURAL0 9TEG]   L;G  #CB OR #FD BITS 
,PLAT=M-DEP5D5T "<! S\RCE ( 5D.S PORT+
BUGS">   L;G L;G  #FD BITS  ,GU>ANTE$
#FD-BIT "<,C#II">   FLOAT  #CB BITS 
,S+LE-PRECI.N ,,IEEE #GED   D\BLE  #FD
BITS  ,D\BLE-PRECI.N ,,IEEE #GED  
.-,BOOL _/ BOOL  #A BIT "</OR$ Z #A
BYTE">  ,TRUE_/FALSE   .-,BIT,9T"<;,N"> 
;,N BITS  ,>BITR>Y-WID? 9TEG]S "<,C#BC">
VOID  #J BITS  8,NO VALUE0 OR 8ANY
PO9T]0 ,! FIX$-WID? TYPES F @</D9T4H@> 
9T#H.-T1 U9T#CB.-T1 9T#FD.-T  >E :AT
MOD]N ;,C CODE ACTUALLY USES1 2C !Y
REMOVE ! AMBIGU;Y ( 8H[ WIDE IS L;G ON ?
>*ITECTURE40
,PO9T]S
,PO9T]S >E ,C'S MO/ P[];L & MO/ DANG]\S
F1TURE4 ,A PO9T] IS AN ADDRESS 9 MEMORY4
,Y C3
- ,D]EF];E X "<"9P"> TO R1D OR WRITE !
VALUE AT T ADDRESS - ,P]=M >I?METIC ON X
"<;P "6 #C M1NS 8?REE ELE;TS PA/ ;P0"> -
,CA/ X TO ANY O!R PO9T] TYPE  9CLUD+
TYPES T >E COMPLETELY WR;G - ,PASS X TO
A FUNC;N1 : C !N MODIFY ! ORIG9AL DATA
VOID SWAP"<9T "9A1 9T "9B"> _<     9T
TMP "7 "9A2     "9A "7 "9B2     "9B "7
TMP2 _>
,PO9T]S >E :AT MAKE ;,C A SY/EMS
LANGUAGE4 ,!Y GIVE ! PROGRAMM] DIRECT
A3ESS TO MEMORY  TO H>DW>E REGI/]S1 TO
,,DMA BU6]S1 TO NET"W PACKET H1D]S1 TO
K]NEL DATA /RUCTURES4 ,!Y >E AL :AT MAKE
;,C DANG]\S3 A PO9T] TO FRE$ MEMORY1 A
PO9T] PA/ ! 5D ( AN >RAY1 A NULL PO9T]
D]EF];E1 A PO9T] TO ! WR;G TYPE  ALL (
^! COMPILE )\T W>N+ & CRA% "<OR WORSE1
CORRUPT DATA SIL5TLY"> AT RUN"T4
,! 5TIRE PHILOSOPHY ( ,RU/ C 2 "U/OOD Z3
8,:AT IF WE CD H PO9T]S1 B ! COMPIL]
V]IFI$ !Y 7 ALW VALID80
,UNDEF9$ 2HAVIOR
,C'S MO/ 3TROV]SIAL F1TURE IS UNDEF9$
2HAVIOR "<,,UB">4 ,! /&>D DEF9ES C]TA9
OP]A;NS Z HAV+ NO REQUIR$ 2HAVIOR  !
COMPIL] MAY D ANY?+1 9CLUD+ PRODUC+
APP>5TLY CORRECT CODE T BR1KS 9 SUBTLE
WAYS4
,! CLASSIC EXAMPLES3
- ,SIGN$ 9TEG] OV]FL[ "<,,9T.-,,MAX "6
#A">  UNDEF9$ - ,D]EF]5C+ A NULL PO9T] 
UNDEF9$ - ,A3ESS+ AN >RAY \ ( B.DS 
UNDEF9$ - ,US+ A V>IABLE 2F 9ITIALIZ+ X 
UNDEF9$ - ,MODIFY+ A VALUE TWICE 2T
SEQU;E PO9TS  UNDEF9$
,! RA;NALE IS P]=M.E3 BY L1V+ ^! CASES
UNDEF9$1 ! COMPIL] C ASSUME !Y N"E
HAPP51 5ABL+ OPTIMIZA;NS T WD 2
IMPOSSIBLE IF E $GE CASE _H TO 2 DEF9$4
,A COMPIL] T "KS SIGN$ OV]FL[ _C HAPP5 C
OPTIMIZE "<;X "6 #A"> @> ;X TO TRUE )\T
*ECK+4 ,A COMPIL] T "KS NULL D]EF];E _C
HAPP5 C ELIM9ATE NULL *ECKS4
,! CO/ IS T ,,UB IS ! S\RCE ( A VA/
NUMB] ( SECUR;Y VULN]ABILITIES4 ,BU6]
OV]FL[S "<UNDEF9$ 2HAVIOR"> >E ! S+LE
MO/ EXPLOIT$ BUG CLASS 9 ! HI/ORY (
COMPUT+4 ,! T5.N 2T ,C'S P]=M.E & ,C'S
SAFETY IS ! C5TRAL DRAMA ( SY/EMS
PROGRAMM+1 & X HAS DRIV5 ! CR1;N ( SAF]
ALT]NATIVES  ,RU/1 ,ZIG1 ,C>BON  T TRY
TO PRES]VE ,C'S P]=M.E :ILE ELIM9AT+
"<OR AT L1/ 3TA9+"> ,,UB4
8;,C IS A RAZOR-%>P TOOL ) : "O C CR1TE
AN ELEGANT & E6ICI5T PROGRAM  OR CUT "OF
9 WAYS T >E EXQUISITELY DI6ICULT TO
DIAGNOSE40  P>APHRAS$ F NUM]\S ;,C
PRACTI;N]S
,": ;,C RUNS  /1 9 #BJBF
;,C IS N DECL9+4 ,X O3UPIES A DI6]5T
NI*E ?AN X DID 9 #AIIJ  X IS NO L;G] !
DEFAULT *OICE = APPLICA;N PROGRAMM+  B 9
XS DOMA91 X REMA9S UN*ALL5G$3
,OP]AT+ SY/EM K]NELS  ,L9UX "<#CJ"6
MILLION L9ES ( ;,C">1 ,W9D[S K]NEL1
MAC,O,S_/I,O,S "<,,XNU K]NEL">1 ,&ROID'S
H>DW>E AB/RAC;N LAY]1 ! ,B,S,DS1
,ZEPHYR1 ,FREE,R,T,O,S1 E ,,RTOS ON E
MICROCONTROLL]4 ,OP]AT+ SY/EM K]NELS >E
,C'S HOME T]RITORY1 & :ILE ,RU/ IS MAK+
9ROADS "<,L9UX N[ A3EPTS ,RU/ DRIV]S">1
! VA/ MAJOR;Y ( K]NEL CODE REMA9S & W
REMA9 ;,C = DECADES4
,EMB$D$ SY/EMS  ,F ! @S#J4JC
MICROCONTROLL] 9 A WA%+ MA*9E TO ! FLI<T
COMPUT] 9 A SATELLITE1 EMB$D$ S(TW>E IS
OV]:ELM+LY ;,C4 ,! R1SONS >E PRACTICAL3
;,C COMPIL]S EXI/ = E ,,CPU >*ITECTURE
"E MANUFACTUR$1 ! LANGUAGE HAS NO HIDD5
ALLOCA;NS OR RUN"T OV]H1D1 & ! G5]AT$
CODE MAPS PR$ICTABLY TO MA*9E 9/RUC;NS4
,:5 Y H #B,,KB ( ,,RAM & A #AF,M,HZ
CLOCK1 Y _C AF=D A G>BAGE COLLECTOR1 A
RUN"T1 OR A VIRTUAL MA*9E4 ,,>M1
,,RISC-;,V1 ,,MIPS1 ,,AVR1 ,,PIC1
,,MSP#DCJ1 ,XT5SA1 ,SUP],H  E 9/RUC;N
SET >*ITECTURE %IPS ) A ;,C COMPIL]1
USUALLY Z ! PRIM>Y DEVELOP;T TOOL4 ,!
EMB$D$ _W RUNS ON ;,C 2C "! IS LIT]ALLY
NO ALT]NATIVE ) EQUIVAL5T H>DW>E
SUPPORT4
,COMPIL]S & 9T]PRET]S  ,,GCC1
,CLANG_/,,LLVM'S ;,C FRONT5D1 ,C,PY?ON
"<! REF];E ,PY?ON IMPLE;TA;N">1 ! ,RUBY
9T]PRET] "<,C,RUBY_/,,MRI">1 ,,PHP1
,P]L1 ,LUA1 ;,R  ALL WRITT5 9 ;,C4 ,EV5
COMPIL]S = LANGUAGES DESIGN$ TO REPLACE
;,C >E (T5 WRITT5 9 ;,C !MVS1 AT L1/
9ITIALLY4
,DATABASES  ,S,Q,LITE "<! MO/ WIDELY
DEPLOY$ DATABASE 9 ! _W  X RUNS ON E
SM>TPH"O">1 ,PO/GRE,S,Q,L1 ,MY,S,Q,L1
,R$IS  ALL ;,C4
,NET"W+  ,! ,L9UX NET"W+ /ACK1
,OP5,S,S,L_/,LIBRE,S,S,L1 ,,NG9X1 CURL1
,,DNS RESOLV]S1 PACKET PROCESS+ FRAME"WS
;,C DOM9ATES ! LAY] 2T ! APPLICA;N & !
WIRE4
,! ;,C /&>D LIBR>Y XF  GLIBC1 MUSL1
BIONIC "<,&ROID">1 NEWLIB "<EMB$D$">  ^!
>E ! F.DA;NAL LIBR>IES T E PROGRAM ON A
,UNIX-L SY/EM L9KS AG/1 & !Y >E WRITT5 9
;,C4
,S,Q,LITE1 WRITT5 9 ;,C1 IS E/IMAT$ TO
RUN ON OV] #D BILLION DEVICES4 ,X IS 9 E
I,PH"O1 E ,&ROID PH"O1 E ,MAC1 E ,W9D[S
#AJ"6 MA*9E "<VIA ,$GE_/,*ROME">1 E
,FIREFOX1 E MAJOR WEB FRAME"W'S
DEVELOP;T MODE1 E ,SKYPE CLI5T1 & MO/
TELEVI.N FIRMW>E4 ,X MAY 2 ! MO/ WIDELY
DEPLOY$ S(TW>E COMPON5T 9 HI/ORY  & X IS
#AEC1JJJ L9ES ( ;,C1 MA9TA9$ BY ?REE P1
) #AJJ.0 BRAN* COV]AGE 9 XS TE/ SUITE4
,C'S LEGACY 9 O!R LANGUAGES
,C'S SYNTAX1 SEMANTICS1 & PHILOSOPHY H
BE5 REPLICAT$ S ?OR\<LY T 8;,C-FAMILY
LANGUAGE0 IS A RECOGNIZ$ CATEGORY 3TA9+
MO/ ( ! _W'S PROGRAMM+ LANGUAGES3
,LANGUAGE  ,YE>  ,RELA;N%IP TO ;,C  
,C"6"6  #AIHE  8;,C ) ,CLASSES0  SUP]SET
( ;,C ) ,,OOP1 TEMPLATES1 ,,RAII  
,OBJECTIVE-;,C  #AIHD  ;,C )
,SMALLTALK-/YLE MESSAGE PASS+  !
LANGUAGE ( MAC,O,S_/I,O,S UNTIL ,SWIFT  
,JAVA  #AIIE  ,C'S SYNTAX ) G>BAGE
COLLEC;N1 A VIRTUAL MA*9E1 & NO PO9T]S 
DESIGN$ TO 2 8,C"6"6 )\T ! GUNS0  
,JAVA,SCRIPT  #AIIE  ,C'S SYNTAX APPLI$
TO A PROTOTYPE-BAS$ SCRIPT+ LANGUAGE  N[
! MO/-US$ LANGUAGE ON ,E>?   ,C_?  #BJJJ
,MICROS(T'S ANSW] TO ,JAVA  ,C'S SYNTAX
ON A MANAG$ RUN"T   ,,PHP  #AIIE  ,C'S
SYNTAX APPLI$ TO S]V]-SIDE WEB SCRIPT+  
,P]L  #AIHG  ,H1VY ;,C 9FLU;E 9 SYNTAX &
SEMANTICS   ;,D  #BJJA  ,DESIGN$ Z 8:AT
,C"6"6 %D H BE50  ;,C-COMPATIBLE ) A
,,GC OP;N   ,G  #BJJI  ,K5 ,?OMPSON &
,ROB ,PIKE'S RE?9K+ ( ;,C = NET"W$
SY/EMS  NO CLASSES1 NO EXCEP;NS1
G>BAGE-COLLECT$   ,RU/  #BJAE  ,DESIGN$
TO REPLACE ;,C 9 SY/EMS PROGRAMM+ BY
SOLV+ MEMORY SAFETY AT COMPILE "T  
,SWIFT  #BJAD  ,APPLE'S REPLACE;T =
,OBJECTIVE-;,C  ;,C-9FLU;ED B
MEMORY-SAFE   ,ZIG  #BJAF  ,A 8BETT]
;,C0  ;,C 9T]OP1 NO HIDD5 3TROL FL[1
COMP"T ,! _<1 _>1 21 ="<22">1 IF"<">1
:ILE"<">1 RETURN1 9T1 VOID1 PR9TF  ^! >E
;,C4 ,E PROGRAMM] 9 ! _W "KS ,C'S
SYNTAX1 :E!R !Y "K ;,C OR N4
,! P
,C'S CR1;N 0 %AP$ BY A REM>KABLY SMALL
GR\P ( P1 ALL AT ,BELL ,LABS3
,D5NIS ,RIT*IE "<#AIDA#BJAA"> DESIGN$ &
IMPLE;T$ ;,C4 ,HE AL CO-DESIGN$ ,UNIX )
,K5 ,?OMPSON4 ,HE RCVD ! ,TUR+ ,AW>D 9
#AIHC "<%>$ ) ,?OMPSON"> & ! ,NA;NAL
,M$AL ( ,TE*NOLOGY 9 #AIIH4 ,HE DI$ ON
,OCTOB] #AB1 #BJAA1 J "DS AF ,/EVE ,JOBS
A CO9CID;E T DREW ATT5;N TO H[ M* ( !
TE*NOLOGY T ,JOBS MADE FAM\S RAN ON
,RIT*IE'S S(TW>E4 ,RIT*IE'S D1? 0 B>ELY
NOTIC$ \TSIDE ! TE*NICAL COMMUN;Y1 : _M
REG>D$ Z A PR(.D 9JU/ICE4
,K5 ,?OMPSON DESIGN$ ! ;,B LANGUAGE & !
ORIG9AL ,UNIX4 ,HE LAT] CO-CR1T$ ! ,G
PROGRAMM+ LANGUAGE AT ,GOOGLE  A
LANGUAGE T IS1 9 _M WAYS1 A RE?9K+ ( !
SAME SY/EMS PROGRAMM+ SPACE T ;,C &
,UNIX O3UPI$1 9=M$ BY DECADES ( H9DSI<T4
,BRIAN ,K]NI<AN CO-AU?OR$ ,! ;,C
,PROGRAMM+ ,LANGUAGE & "ND ! LANGUAGE'S
F/ PROGRAM4 ,HE DID N DESIGN ;,C1 B 8
WRIT+ MADE X A3ESSIBLE TO A G5]A;N (
PROGRAMM]S4 ,HE AL CO-DESIGN$ ,,AWK &
3TRIBUT$ TO ,UNIX'S DOCU;TA;N & CULTURE4
,/EVE ,JOHNSON WROTE ,,PCC "<,PORTABLE
;,C ,COMPIL]">1 : 2CAME ! /&>D ;,C
COMPIL] ON MO/ ,UNIX SY/EMS & DEMON/RAT$
T ;,C COMPIL]S CD 2 PORT$ 2T >*ITECTURES
CRITICAL EVID;E = ,C'S PORTABIL;Y
PROMISE4
,! COMPIL]S
,,GCC
,! ,,GNU ,COMPIL] ,COLLEC;N1 />T$ BY
,RI*>D ,/ALLMAN 9 #AIHG1 2CAME ! DOM9ANT
;,C COMPIL] BY ! LATE #AIIJ;S & REMA9$ S
= OV] TWO DECADES4 ,,GCC'S OPTIMIZA;N
CAPABILITIES1 XS SUPPORT = VIRTUALLY E
,,CPU >*ITECTURE1 & XS ROLE Z ! DEFAULT
COMPIL] = ,L9UX MADE X ! DE FACTO /&>D4
,Z ( #BJBF1 ,,GCC SUPPORTS ,C#BC
SUB/ANTIALLY4
,CLANG _/ ,,LLVM
,CLANG1 ! ;,C FRONT5D = ! ,,LLVM COMPIL]
9FRA/RUCTURE1 EM]G$ F ,APPLE & !
,UNIV]S;Y ( ,ILL9OIS 9 ! LATE #BJJJ;S4
,XS ADVANTAGES  DRAMATICALLY FA/]
COMPILE "TS1 BETT] ]ROR MESSAGES1 A
MODUL> >*ITECTURE1 & A P]MISSIVE
"<NON-,,GPL"> LIC5SE  MADE X ! DEFAULT
COMPIL] ON MAC,O,S1 I,O,S1 ,FREE,B,S,D1
& ,&ROID4 ,_M ,L9UX 4TRIBU;NS N[ (F]
,CLANG Z AN ALT]NATIVE TO ,,GCC4
,CLANG'S ,C#BC SUPPORT IS EXT5SIVE4
,,MSVC
,MICROS(T'S ,VISUAL ,C"6"6 COMPIL]
HI/ORICALLY LA7$ 2H ,,GCC & ,CLANG 9 ;,C
/&>D SUPPORT4 ,,MSVC'S ;,C SUPPORT 0
FROZ5 AT ,C#HI = NE>LY TWO DECADES  !
COMPANY FOCUS$ ON ,C"6"6 & 3SID]$ ;,C A
SECOND>Y 3C]N4 ,? /.E S(T5$
SIGNIFICANTLY 9 ! #BJAJ;S1 & ,,MSVC N[
SUPPORTS MO/ ( ,C#AA & ,C#AG1 ) ,C#BC
SUPPORT 9 PROGRESS4
,,TCC1 ,,PCC1 & O!RS
,,TCC "<,T9Y ;,C ,COMPIL]">1 WRITT5 BY
,FABRICE ,BELL>D1 COMPILES ;,C S FA/ T X
C 2 US$ Z A SCRIPT+ 9T]PRET]  TCC -RUN
HELLO4C COMPILES & EXECUTES 9 A S+LE
/EP4 ,,PCC HAS BE5 REVIV$ Z A SMALL1
CL1N1 /&>DS-COMPLIANT COMPIL]4 CPROC
T>GETS ,,QBE4 *IBICC1 BY ,RUI ,UEYAMA1
IS A DELIB]ATELY $UCA;NAL SMALL ;,C
COMPIL] T C COMPILE R1L ;,C PROGRAMS
:ILE REMA9+ R1DABLE 5 TO S]VE Z A T1*+
TOOL4 ,! ECOSY/EM ( SMALL1 FOCUS$ ;,C
COMPIL]S REMA9S VIBRANT  A TE/A;T TO !
LANGUAGE'S RELATIVE SIMPLIC;Y "<! 5TIRE
,C#BC GRAMM> FITS 9 A FEW PAGES ( ,,BNF1
COMP>$ TO ,C"6"6'S HUNDR$S">4
,! DIV]S;Y ( ;,C COMPIL]S MATT]S
PRACTICALLY3 X M1NS ;,C CODE C 2 COMPIL$
= ANY ,,CPU >*ITECTURE1 ANY OP]AT+
SY/EM1 & ANY =M FACTOR F A SM>TWAT* TO A
SUP]COMPUT]4 ,NO O!R LANGUAGE 9 #BJBF C
CLAIM COMPIL] SUPPORT Z BROAD Z ,C'S4
;,C 9 SAFETY-CRITICAL & R1L-"T SY/EMS
;,C DOM9ATES SAFETY-CRITICAL S(TW>E  !
CODE ": FAILURE M1NS PHYSICAL H>M4
,AVIA;N "<,,D-#AGH;;,C">1 AUTOMOTIVE
"<,,ISO #BFBFB">1 M$ICAL DEVICES "<,,IEC
#FBCJD">1 NUCLE> P[]1 & RAILWAY SIGNAL+
ALL USE ;,C EXT5SIVELY1 GOV]N$ BY COD+
/&>DS T RE/RICT ! LANGUAGE TO A SAFE
SUBSET3
,,MISRA ;,C  ! ,MOTOR ,9DU/RY ,S(TW>E
,RELIABIL;Y ,ASSOCIA;N'S GUIDEL9ES1
ORIG9ALLY PUBLI%$ 9 #AIIH1 DEF9E A
RE/RICT$ SUBSET ( ;,C = SAFETY-CRITICAL
AUTOMOTIVE S(TW>E4 ,,MISRA ;,C BANS OR
RE/RICTS DYNAMIC MEMORY ALLOCA;N
"<MALLOC_/FREE">1 RECUR.N1 GOTO1 PO9T]
>I?METIC1 & M* ( ! PREPROCESSOR4 ,!
RESULT IS A SUBSET ( ;,C T IS
ANALYZABLE1 TE/ABLE1 & PR$ICTABLE  AT !
CO/ ( EXPRESSIVE;S4 ,,MISRA ;,C HAS BE5
ADOPT$ F> 2Y AUTOMOTIVE3 M$ICAL DEVICES1
AVIONICS1 & 9DU/RIAL 3TROL SY/EMS ALL
USE X4
,,C]T ;,C  ! ,,,SEI C]T ;C,' ,COD+ ,/&>D
FOCUSES ON SECUR;Y R ?AN SAFETY1 PROVID+
RULES = AVOID+ EXPLOITABLE
VULN]ABILITIES4 ,X ADDRESSES BU6]
OV]FL[S1 9TEG] OV]FL[S1 RACE 3DI;NS1 & !
MO/ DANG]\S UNDEF9$ 2HAVIOR PATT]NS4
,/ATIC ANALYSIS  TOOLS L ,COV];Y1
,POLYSPACE1 ,,PC-L9T1 & ! ,CLANG ,/ATIC
,ANALYZ] P]=M AUTOMAT$ *ECK+ ( ;,C CODE
= COMMON DEFECTS4 ,! /ATE ( ! >T C F9D
NULL PO9T] D]EF];ES1 BU6] OV]FL[S1
RES\RCE L1KS1 & D1D CODE AUTOMATICALLY 
B NO /ATIC ANALYZ] C CAT* ALL BUGS 9
;,C1 2C ! LANGUAGE'S SEMANTICS MAKE _M
9T]E/+ PROP]TIES UNDECIDABLE4
,! IRONY IS CLE>3 ! LANGUAGE MO/ US$ 9
SAFETY-CRITICAL SY/EMS IS ! LANGUAGE L1/
EQUIPP$ TO PREV5T BUGS4 ,! 9DU/RY
COMP5SATES ) PROCESS1 TE/+1 & TOOL+ 
COD+ /&>DS1 /ATIC ANALYSIS1 ,,MC_/,,DC
COV]AGE REQUIRE;TS1 =MAL V]IFICA;N 
PRECISELY 2C ! LANGUAGE XF PROVIDES NO
SAFETY NET4 ,? IS ! FUNDA;TAL T5.N T
DRIVES ! ADOP;N ( MEMORY-SAFE LANGUAGES
9 SAFETY-CRITICAL DOMA9S4
;,C & ,C"6"63 ! RELA;N%IP
;,C & ,C"6"6 >E N ! SAME LANGUAGE4
,C"6"6 0 DESIGN$ BY ,BJ>NE ,/R\/RUP />T+
9 #AIGI Z 8;,C ) ,CLASSES10 & X %>ES
,C'S SYNTAX & M* ( XS SEMANTICS4 ,B !
LANGUAGES H DIV]G$ SIGNIFICANTLY3
- ,C"6"6 HAS TEMPLATES1 CLASSES1 VIRTUAL
FUNC;NS1 EXCEP;NS1 ,,RAII1 MOVE
SEMANTICS1 3CEPTS1 MODULES1 COR\T9ES1 &
A /&>D LIBR>Y T 9CLUDES 3TA9]S1
ALGORI?MS1 & SM>T PO9T]S - ;,C HAS N"O (
^!  & ? IS A F1TURE1 N A DEFICIT
,C'S SIMPLIC;Y IS XS VALUE4 ,A ;,C
PROGRAM'S 2HAVIOR MAPS PR$ICTABLY TO
MA*9E CODE4 ,! LANGUAGE HAS NO HIDD5
3/RUCTORS1 NO IMPLICIT FUNC;N CALLS1 NO
TEMPLATE 9/ANTIA;N1 NO EXCEP;N UNW9D+
TABLES4 ,? PR$ICTABIL;Y IS :Y ;,C REMA9S
PREF]R$ = K]NELS1 FIRMW>E1 &
SAFETY-CRITICAL SY/EMS ": E 9/RUC;N M/ 2
A3.T$ =4
,! RELA;N%IP IS "S"TS 3T5TI\S4 ,C"6"6
PROGRAMM]S >GUE T ,C'S LACK ( SAFETY
F1TURES IS 9EXCUSABLE 9 #BJBF4 ;,C
PROGRAMM]S >GUE T ,C"6"6'S COMPLEX;Y IS
XF A S\RCE ( BUGS4 ,! ,L9UX K]NEL1 ! MO/
IMPORTANT ;,C PROJECT 9 ! _W1 EXPLICITLY
PROHIBITS ,C"6"6 & ALW HAS  ,L9US
,TORVALDS' OP9IONS ON ,C"6"6 >E
WELL-DOCU;T$ & UNPR9TABLE ON A FAMILY
WIKI4
,! H"O/ CRITIQUE
,C'S W1K;SES >E WELL-"KN & S]I\S3
,MEMORY SAFETY IS ! PROGRAMM]'S PROBLEM4
;,C PROVIDES NO PROTEC;N AG/ BU6]
OV]FL[S1 USE-AF-FREE1 D\BLE-FREE1 NULL
PO9T] D]EF];ES1 OR DATA RACES4 ,!
PROGRAMM] IS RESPONSIBLE = GETT+ E
ALLOCA;N1 E B.DS *ECK1 & E FREE CORRECT4
,9 L>GE CODEBASES1 ? IS /ATI/ICALLY
IMPOSSIBLE  ,MICROS(T1 ,GOOGLE1 & ,APPLE
ALL REPORT T R\<LY #GJ.0 ( _! SECUR;Y
VULN]ABILITIES >E MEMORY SAFETY ISSUES 9
;,C & ,C"6"6 CODE4
,/R+ H&L+ IS T]RIBLE4 ,NULL-T]M9AT$ /R+S
>E A DESIGN DECI.N F #AIGB T HAS CAUS$
9CALCULABLE DAMAGE4 /RCPY DOESN'T *ECK
B.DS4 GETS 0 S DANG]\S X 0 REMOV$ F !
/&>D4 /RCAT REQUIRES ! PROGRAMM] TO
TRACK BU6] SIZES MANUALLY4 ,EV5 SNPR9TF1
! 8SAFE0 ALT]NATIVE1 REQUIRES !
PROGRAMM] TO PASS ! CORRECT BU6] SIZE4
,! PREPROCESSOR IS A BLUNT 9/RU;T4
_?DEF9E1 _?9CLUDE1 _?IFDEF  ! ;,C
PREPROCESSOR OP]ATES ON TEXT1 N ON !
LANGUAGE'S SYNTAX OR TYPE SY/EM4 ,X
5ABLES MACROS T LOOK L FUNC;NS B DON'T
RESPECT SCOP+1 _?9CLUDE T COPIES 5TIRE
FILES TEXTUALLY 9TO EA* TRANSLA;N UNIT
"<CAUS+ 5ORM\S COMPILA;N OV]H1D">1 &
3DI;NAL COMPILA;N T CR1TES AN EXPON5TIAL
SPACE ( POSSIBLE PROGRAMS T >E
IMPOSSIBLE TO TE/ EXHAU/IVELY4
,UNDEF9$ 2HAVIOR IS A LOAD$ GUN4 ,! LI/
( ,,UB 9 ;,C IS 5ORM\S1 & MOD]N OPTIMIZ+
COMPIL]S EXPLOIT X A7RESSIVELY4 ,CODE T
8"WS0 9 DEBUG MODE C BR1K SIL5TLY 9
REL1SE MODE 2C ! OPTIMIZ] REMOV$ A NULL
*ECK T ! PROGRAMM] ?"\ 0 A SAFETY NET4
,! GAP 2T :AT ;,C PROGRAMM]S ?9K _! CODE
DOES & :AT ! /&>D SAYS X DOES IS ! S\RCE
( "S ( ! MO/ SUBTLE & DANG]\S BUGS 9
SY/EMS S(TW>E4
,! BUILD SY/EM IS *AOS4 ;,C HAS NO /&>D
BUILD SY/EM1 NO /&>D PACKAGE MANAG]1 NO
/&>D DEP5D5CY RESOLU;N4 ,PROJECTS USE
,MAKE1 ,C,MAKE1 ,MESON1 ,AUTOTOOLS1
,N9JA1 OR CU/OM SCRIPTS4 ,"! IS NO C>GO
BUILD1 NO G BUILD1 NO NPM 9/ALL4 ,? IS
,C'S MO/ SIGNIFICANT PRACTICAL
4ADVANTAGE COMP>$ TO MOD]N LANGUAGES4
,^! >E N !ORETICAL 3C]NS4 ,!Y >E ! DAILY
R1L;Y ( ;,C PROGRAMM+ 9 #BJBF1 & !Y >E
:Y LANGUAGES L ,RU/ EXI/4 ,B !Y >E AL :Y
;,C P]SI/S3 E ALT]NATIVE T ELIM9ATES
,C'S DANG]S AL ELIM9ATES "S ( ,C'S
CAPABILITIES4 ,! LANGUAGE T LETS Y D
ANY?+1 9CLUD+ %OOT YRF1 IS AL ! LANGUAGE
T LETS Y BUILD ANY?+4 ,! TRADE-(F IS
9H]5T1 & FIFTY-F\R YE>S ( HI/ORY SU7E/ T
! 9DU/RY W A3EPT ! DANG] 9 EX*ANGE = !
P[]  AT L1/ = ! CODE T RUNS CLOSE/ TO !
H>DW>E4
,D5NIS ,RIT*IE ON ,C'S PHILOSOPHY3 8;,C
IS QUIRKY1 FLAW$1 & AN 5ORM\S SU3ESS4
,:ILE A3ID5TS ( HI/ORY SURELY HELP$1 X
EVID5TLY SATISFI$ A NE$ = A SY/EM
IMPLE;TA;N LANGUAGE E6ICI5T 5 TO 4PLACE
ASSEMBLY LANGUAGE1 YET SU6ICI5TLY
AB/RACT & FLU5T TO DESCRIBE ALGORI?MS &
9T]AC;NS 9 A WIDE V>IETY ( 5VIRON;TS40 
F 8,! ,DEVELOP;T ( ! ;,C ,LANGUAGE10
#AIIC4
,! FUTURE ( ;,C
;,C IS N DY+1 B XS ROLE IS %IFT+4 ,?REE
TR5DS >E RE%AP+ ,C'S POSI;N 9 #BJBF3
,! MEMORY SAFETY M&ATE4 ,GOV]N;TS &
MAJOR CORPORA;NS >E N[ EXPLICITLY
RECOMM5D+ AG/ NEW ;,C CODE 9 3TEXTS ":
MEMORY-SAFE ALT]NATIVES EXI/4 ,! ,,U
,NA;NAL ,SECUR;Y ,AG5CY1 ! ,:ITE ,H\SE
,(FICE ( ! ,NA;NAL ,CYB] ,DIRECTOR1
,,CISA1 & ! ,,FBI H ALL PUBLI%$ GUID.E
RECOMM5D+ MEMORY-SAFE LANGUAGES4
,GOOGLE1 ,MICROS(T1 & ,APPLE H ALL
PUBLICLY COMMITT$ TO R$UC+ ! AM.T ( NEW
;,C "<& ,C"6"6"> CODE !Y WRITE4 ,! ,L9UX
K]NEL'S ADOP;N ( ,RU/ IS ! MO/ VISIBLE
EXAMPLE ( ? TR5D4
;,C Z A COMPILA;N T>GET4 ,9CR1S+LY1 ;,C
IS US$ N Z A LANGUAGE T HUMANS WRITE1 B
Z A PORTABLE ASSEMBLY LANGUAGE T
COMPIL]S T>GET4 ,LANGUAGES F ,HASKELL
"<,,<C C T>GET ;,C"> TO ,NIM TO ,CY?ON
TO ! ,,ALB ;,C BACK5D ALL COMPILE TO
;,C1 L"EAG+ ,C'S UNIV]SAL COMPIL]
SUPPORT & DECADES ( OPTIMIZA;N
9FRA/RUCTURE4 ,9 ? ROLE1 ,C'S R1DABIL;Y
& ]GONOMICS DON'T MATT]  :AT MATT]S IS T
E PLAT=M HAS A ;,C COMPIL] & T ! G5]AT$
CODE RUNS FA/4
,C#B;Y & 2Y4 ,! ;,C /&>DS COMMITTEE
"<,,WG#AD"> 3T9UES ACTIVE DEVELOP;T4 ,!
NEXT REVI.N1 9=MALLY CALL$ ,C#B;Y1 HAS
XS LATE/ "W+ DRAFT "<,N#CHHF"> F ,MAY
#BJBF4 ,! COMMITTEE IS 3SID]+ F1TURES T
WD H BE5 UN?9KABLE A DECADE AGO  IMPROV$
TYPE 9F];E1 BETT] G5]ICS1 & FUR!R
SAFETY-ORI5T$ F1TURES4 ;,C IS EVOLV+1
SL[LY & C>E;LLY1 9 ! SAME DIREC;N ! RE/
( ! 9DU/RY IS MOV+  B ON XS [N T]MS1 AT
XS [N PACE1 PRES]V+ ! BACKW>D
COMPATIBIL;Y T IS XS GR1TE/ /R5G?4
,! MO/ LIKELY FUTURE IS COEXI/;E4 ,NEW
SAFETY-CRITICAL & HI<-P]=M.E SY/EMS W
9CR1S+LY 2 WRITT5 9 ,RU/ OR O!R
MEMORY-SAFE LANGUAGES4 ,EXI/+ ;,C
CODEBASES  HUNDR$S ( BILLIONS ( L9ES1
REPRES5T+ DECADES ( 9VE/;T  W 3T9UE TO
RUN & 2 MA9TA9$ 9 ;,C4 ,! TWO LANGUAGES
W COEXI/ AT ! ,,FFI B.D>Y1 ) ,RU/ CALL+
;,C LIBR>IES & ;,C K]NELS HO/+ ,RU/
DRIV]S4 ;,C W REMA9 9DISP5SABLE  N 2C X
IS ! BE/ LANGUAGE1 B 2C X IS ! MO/
UNIV]SAL1 ! MO/ PORTABLE1 & ! MO/ DEEPLY
EMB$D$ 9 ! 9FRA/RUCTURE ( ! _W4
;,C & ,,ALB
,! ,,ALB ;,C BACK5D IS ,ADA,LOGIC
,,BASIC'S MO/ COMPLETE EMITT]3 X TURNS
AN ,,ALB PROGRAM 9TO ,C#HI S\RCE CODE1 :
!N COMPILES ON ESS5TIALLY ANY PLAT=M )
ANY COMPIL]4 ,! DELIB]ATE T>GET+ ( ,C#HI
! OLDE/1 MO/ PORTABLE DIALECT  REFLECTS
,C'S UNIQUE POSI;N Z ! UNIV]SAL
COMPILA;N T>GET4 ,": NEW] LANGUAGES
DEBATE : /&>D TO REQUIRE1 ,C#HI REMA9S !
"O DIALECT T E ;,C COMPIL] 9 EXI/;E C
H&LE4
,! ,,ALB PROJECT 9CLUDES ;,C 9 XS
D[NLOAD 4TRIBU;N & USES ;,C Z ! PRO( T
8WRITE ONCE1 COMPILE ANY":0 IS A*IEVABLE
EXACTLY ! SAME PROMISE T ,RIT*IE &
,?OMPSON DEMON/RAT$ :5 !Y PORT$ ,UNIX TO
! ,9T]DATA #H_/#CB 9 #AIGH4
,SEE AL
- ,,ALB ;,C BACK5D  ,ADA,LOGIC ,,BASIC'S
,C#HI EMITT] - ,RU/  ! LANGUAGE DESIGN$
TO PREV5T ,C'S MEMORY SAFETY PROBLEMS -
,,=TRAN  ,,COBOL  ,,LISP  ,,ALGOL  ,C'S
3TEMPOR>IES & PR$ECESSORS - ,HI/ORY (
,PROGRAMM+  ,C'S PLACE 9 ! >C -
,ADA,LOGIC ,,BASIC
,REF];ES
.<#A.> ;,D4 ;,M4 ,RIT*IE1 8,! ,DEVELOP;T
( ! ;,C ,LANGUAGE10 ,,HOPL-,,II3
,PROCE$+S ( ! ,SECOND ,,ACM ,,SIGPLAN
,3F];E ON ,HI/ORY ( ,PROGRAMM+
,LANGUAGES1 ,CAMBRIDGE1 ,,MA1 ,APRIL
#AIIC4 ,AL3
CS4BELL-LABS4COM_/:O_/DMR_/*I/4HTML4
.<#B.> ;,B4 ;,W4 ,K]NI<AN & ;,D4 ;,M4
,RIT*IE1 ,! ;,C ,PROGRAMM+ ,LANGUAGE1
,PR5TICE-,HALL1 #AIGH4 ,SECOND $I;N1
#AIHH4 .<#C.> ,,ISO_/,,IEC #IHII3#BJBD1
8,9=MA;N TE*NOLOGY  ,PROGRAMM+ LANGUAGES
;,C0 "<,C#BC">1 PUBLI%$ ,OCTOB] #BJBD4
,FREELY AVAILABLE DRAFT3 ,N#CBBJ
"<,FEBRU>Y #BJBD">4 .<#D.> ,,ISO_/,,IEC
#IHII3#AIII1 8,PROGRAMM+ LANGUAGES  ;,C0
"<,C#II">4 ,,ISO_/,,IEC #IHII3#BJAA
"<,C#AA">4 ,,ISO_/,,IEC #IHII3#BJAH
"<,C#AG">4 .<#E.> CPPREF];E4COM1
8,HI/ORY ( ;,C10
EN4CPPREF];E4COM_/C_/LANGUAGE_/HI/ORY4
.<#F.> ,,WG#AD PROJECT /ATUS1
OP5-/D4ORG_/,,JTC#A_/,,SC#BB_/,,WG#AD_/WWW_/PROJECTS4HTML4
.<#G.> ,NOKIA ,BELL ,LABS1 8,! ,CR1;N (
! ,,UNIX ,OP]AT+ ,SY/EM10
NOKIA4COM_/BELL-LABS_/UNIX-HI/ORY4
.<#H.> 8,C#BC "<;,C /&>D REVI.N">10
,WIKIP$IA4 ,A3ESS$ ,OCTOB] #BJBF4