Introduction fo Byte-Oriented File Input/Output Routines
Byte-Oriented Input and Output File Open
Byte-Oriented Input and Output File Close
Byte-Oriented Input and Output
Error Return Codes
:Byte-Oriented File Input/Output Routines
     Thå  followinç  documentatioî  coveró thå  serieó  oæ  byte-�
orienteä  filå input/outpuô routineó iî SYSLIB®   Theså  routineó �
allo÷ thå useò tï sequentiallù reaä froí (GET© anä writå tï (PUT© �
á filå oî á byte-for-bytå basis®   Hence¬  theså routineó providå �
aî exceptionallù simplå methoä foò handlinç inpuô froí anä outpuô �
tï á file.
     Á typicaì prograí whicè employó theså routineó musô opeî thå �
requireä fileó beforå doinç anù processing¬ musô theî perforí thå �
processinç  oî thå openeä files¬  anä musô theî closå  thå  fileó �
wheî  thå  processinç ió completå (closinç thå fileó ió  optionaì �
foò inpuô fileó anä mandatorù foò outpuô files).
     SYSLIÂ provideó fouò setó oæ routineó foò byte-orienteä filå �
inpuô anä output®  Theså routineó arå --

Input Open     Output Open     GET    PUT   Input Close  Output Close
----------     -----------     ---    --­   -----------  ------------
 FI0$OPEN       FO0$OPEN      F0$GET F0$PUT  FI0$CLOSE    FO0$CLOSE
 FI1$OPEN       FO1$OPEN      F1$GET F1$PUT  FI1$CLOSE    FO1$CLOSE
 FI2$OPEN       FO2$OPEN      F2$GET F2$PUT  FI2$CLOSE    FO2$CLOSE
 FI3$OPEN       FO3$OPEN      F3$GET F3$PUT  FI3$CLOSE    FO3$CLOSE

     Thió  systeí  allowó  thå useò tï havå uð tï  ¸  fileó  opeî �
simultaneouslù -- fouò arå opeî foò inpuô usinç GEÔ anä fouò  arå �
opeî  foò  outpuô usinç PUT®   Foò example¬  thå followinç  ió  á �
samplå codå sectioî usinç theså routineó foò twï files:


          EXT  FI0$OPEN   ; DECLARE LIBRARY REFERENCES
          EXT  FO0$OPEN
          EXT  FI0$CLOSE
          EXT  FO0$CLOSE
          EXT  F0$GET
          EXT  F0$PUT
          ...
          LXI  D,FCBI    ; PT TO FCB OF INPUT FILE
          CALL FI0$OPEN
          LXI  D,FCBO    ; PT TO FCB OF OUTPUT FILE
          CALL FO0$OPEN
          ...
          [body containing CALL F0$GET and CALL F0$PUT where required]
          ...
          CALL FI0$CLOSE  ; CLOSE FILE
          CALL FO0$CLOSE
          ...
          END
     Notå thaô onlù thå routineó tï bå useä arå referenceä iî thå �
EXÔ statements®   Iæ yoõ dï noô neeä á particulaò routine¬ dï noô �
referencå  it®   Noô  referencinç aî unneedeä  routinå  generallù �
saveó thå overheaä memorù spacå oæ loadinç iô froí thå library.
     Eacè seô oæ INPUÔ OPEN¬  INPUÔ CLOSE¬  OUTPUÔ  OPEN¬  OUTPUÔ �
CLOSE¬  GET¬ anä PUÔ routineó ió containeä iî onå librarù module¬ �
sï  referencinç anù oæ theså routineó causeó thå entirå modulå tï �
bå  loaded¬  anä  alì  thå routineó arå accessablå  tï  thå  useò �
(provideä theù arå mentioneä iî thå externaì definitions© withouô �
anù   additionaì  memorù   overhead®    Specifically¬   FI0$OPEN¬ �
FI0$CLOSE¬  FO0$OPEN¬ FO0$CLOSE¬ F0$GET¬ anä F0$PUÔ arå containeä �
iî onå module¬  anä referencå tï anù oæ theså routineó loadó  thå �
entirå module» thå samå ió truå foò thå otheò setó oæ routines.
     Thå CLOSÅ routinå foò outpuô (FOn$CLOSE© ió ALWAYÓ required» �
iô  filló  thå resô oæ thå currenô blocë witè Ctrl-Ú followeä  bù �
<NULL¾  byteó anä properlù closeó file®   Thå CLOSÅ  routinå  foò �
inpuô (FIn$CLOSE© ió requireä ONLÙ IÆ yoõ arå goinç tï lateò opeî �
anotheò  filå  foò  inpuô usinç thå  correspondinç  OPEΠ routinå �
(FIn$OPEN)®   FIn$CLOSÅ  onlù serveó tï reseô thå OPEÎ flaç (useä �
tï GEÔ tï ascertaiî thaô thå filå haó beeî properlù opened).
:FI$OPEN and FO$OPEN, et al -- Byte-Oriented Input and Output File Open
     Routine Names:  FI0$OPEN, FI1$OPEN, FI2$OPEN, FI3$OPEN
     Functionº
          Opeî  thå filå whoså FCÂ ió pointeä tï bù DÅ foò  inpuô �
(uså  witè  F$GET)®   FIn$OPEΠ initializeó thå  FC  fields¬  sï �
further initialization is not necessary.
     Inputs:  DE = ptr to FCB of file to open
     Outputs:  Z Flag is Error Indicator, A is Error Code
     Registers Affected:  PSW
     SYSLIB Routines Called:  Internal
     Special Error Conditions:  See Section on Error Codes

     Routine Names:  FO0$OPEN, FO1$OPEN, FO2$OPEN, FO3$OPEN
     Functionº
          Opeî thå filå whoså FCÂ ió pointeä tï bù DÅ foò  outpuô �
(uså  witè  F$PUT)®   FOn$OPEÎ initializeó  thå  FC  fields¬  sï �
furtheò  initializatioî  ió noô necessary®   Iô alsï createó  thå �
indicated file if it does not already exist.
     Inputs:  DE = ptr to FCB of file to open
     Outputs:  Z Flag is Error Indicator, A is Error Code
     Registers Affected:  PSW
     SYSLIB Routines Called:  Internal
     Special Error Conditions:  See Section on Error Codes
:FI$CLOSE and FO$CLOSE, et al -- Byte-Oriented Input and Output File Close
     Routine Names:  FI0$CLOSE, FI1$CLOSE, FI2$CLOSE, FI3$CLOSE
     Functionº
          Closå  thå filå previouslù openeä bù thå  correspondinç �
FI$OPEΠ routine®   Uså  oæ  theså routineó ió  optionaì  iæ  thå �
anotheò  filå  wilì  noô bå openeä lateò iî thå  prograí  bù  thå �
correspondinç FI$OPEÎ routine.
     Inputs:  -None-
     Outputs:  Z Flag is Error Indicator, A is Error Code
     Registers Affected:  PSW
     SYSLIB Routines Called:  Internal
     Speciaì Erroò Conditions:  See Section on Error Codes

     Routine Names:  FO0$CLOSE, FO1$CLOSE, FO2$CLOSE, FO3$CLOSE
     Functionº
          Closå  thå filå previouslù openeä bù thå  correspondinç �
FO$OPEÎ routine®  Uså oæ theså routineó ió MANDATORÙ afteò outpuô �
tï thå filå (usinç thå correspondinç F$PUÔ routine© ió complete.
     Inputs:  -None-
     Outputs:  Z Flag is Error Indicator, A is Error Code
     Registers Affected:  -None-
     SYSLIB Routines Called:  Internal
     Speciaì Erroò Conditions:  See Section on Error Codes
:F$GET and F$PUT, et al -- Byte-Oriented Input and Output
     Routine Names:  F0$GET, F1$GET, F2$GET, F3$GET
     Functionº
          Geô thå nexô bytå iî sequencå froí thå filå  previouslù �
openeä bù thå correspondinç FI$OPEÎ routine®  Bytå ió returneä iî �
Registeò A.
     Inputs:  -None-
     Outputs:  A = Next byte from file if no error
               If Error, NZ and A = Error Code
     Registers Affected:  PSW
     SYSLIB Routines Called:  Internal
     Speciaì Erroò Conditions:  See Section on Error Codes

     Routine Names:  F0$PUT, F1$PUT, F2$PUT, F3$PUT
     Functionº
          Puô  thå  bytå iî Registeò Á ontï thå enä oæ  thå  filå �
previouslù openeä bù thå correspondinç FO$OPEÎ routine.
     Inputs:  A = Byte to PUT
     Outputs:  Z Flag is Error Indicator, A is Error Code
     Registers Affected:  PSW
     SYSLIB Routines Called:  Internal
     Speciaì  Erroò Conditionsº  See Section on Error Codes
:Error Return Codes

     Foò  eacè oæ thå routineó iî thió seô oæ byte-orienteä  filå �
I/Ï routines¬ thå Zerï Flaç anä thå Á Registeò plaù á keù rolå iî �
indicating the error conditions of the routines.

     Iæ  thå  Zerï  Flaç  ió Seô (Z© afteò  á  routinå  haó  beeî �
executed¬  theî thió indicateó thaô nï erroò haó occurred®  Thå Á �
Registeò  ió  eitheò  unaffecteä (iî mosô cases©  oò  containó  á �
returned value (if so indicated, as in Fn$GET routines).

     Iæ  thå  Zerï Flaç ió Cleaò (NZ© afteò á  routinå  haó  beeî �
executed¬  theî thió indicateó thaô aî erroò haó occurred®  Thå Á �
Registeò  no÷  containó  thå Erroò  Code®   Thå  followinç  tablå �
summarizeó  thå  Erroò  Codeó  whicè maù bå  returneä  iî  thå  Á �
Register.

     The following screen display summarizes the Error Codes.


                     Summary of Error Codes
           Returned by Byte-Oriented File I/O Routines

          Code Meaning
          ---- -------

            1  GET or PUT attempted on an unopened file
            2  Disk Full (Ran out of space)
            3  Input File Not Found
            4  Attempt to Read Past EOF
            5  Directory Full
            6  Error in Closing a File
            7  Attempt to Open a File which is already Open