I$IO

The I$IO routine provides a low-level interface to indexed files allowing them to be managed without knowing their FD.

The routine is not affected by iscobol.file.prefix, iscobol.file.suffix and iscobol.file.index.strip_extension (boolean) configuration properties.

Syntax:

CALL "I$IO" USING opCode                     parameters             GIVING returnCode

Parameters:

opCode	Specifies the file handling function to be performed.   Valid values, defined in isfilesys.def are:
	OPEN-FUNCTION	Opens an existing file
	CLOSE-FUNCTION	Closes an opened file
	MAKE-FUNCTION	Creates an empty file
	INFO-FUNCTION	Returns file information
	READ-FUNCTION	Reads a specific record of a file
	NEXT-FUNCTION	Reads the next record of a file
	PREVIOUS-FUNCTION	Reads the previous record of a file
	START-FUNCTION	Sets the file pointer on a specific record
	WRITE-FUNCTION	Writes data into file
	REWRITE-FUNCTION	Rewrites data into file
	DELETE-FUNCTION	Deletes data from file
	UNLOCK-FUNCTION	Unlocks all locked records in a file
	REMOVE-FUNCTION	Removes file from disc
	FLUSH-FUNCTION	Flushes all data to disc
	START-TRANSACTION-FUNCTION	Begins a transaction
	COMMIT-TRANSACTION-FUNCTION	Commits a transaction
	ROLLBACK-FUNCTION	Rollbacks a transaction
	RECOVER-FUNCTION	Rolls forward a transaction
	IN-TRANSACTION-FUNCTION	Tests if transaction is finished
parameters	Parameters depend on the opcode.

Return code:

returnCode contains useful information such as file handles and record sizes or zero if an error occurs. Check the external variable F_ERRNO for additional information on the error.

Examples:

Example - Create an empty file with 1 key and 22 characters records lenght

*> 01 record.       *>  03 rec-key    pic 99.  *> This is the record key       *>  03 rec-data   pic x(20).   working-storage section. copy "isgui.def". copy "isfilesys.def". 77  f                       handle . 77  file-io                 pic x(128). 77  key-io                  pic x(10).         procedure division. create-file.    move "iss-file-io" to file-io    move zero to block-multiple pre-allocation-amount                  extension-amount compression-factor encrypted-flag    move 22 to max-rec-size    move 22 to min-rec-size    move 1 to num-keys    move "1,0,2,0" to key-io    inspect file-io replacing trailing spaces by low-value    inspect key-io  replacing trailing spaces by low-value    inspect logical-info  replacing trailing spaces by low-value    set make-function to true                          call "i$io" using io-function, file-io, 0, physical-info,                                            logical-info, key-io, 0        if f_errno not = 0       display message "I$IO Error: make : " f_errno     end-if    goback.

Example - Open a file on I-O mode, get the record count, then close it

working-storage section. copy "isgui.def". copy "isfilesys.def". 77  f                       handle . 77  file-io                 pic x(128). 77  key-io                  pic x(10).   procedure division. ... open-io.                         move "iss-file-io" to file-io    move 22 to max-rec-size    move 22 to min-rec-size    move  2 to num-keys    set open-function to true    move fio to open-mode        call "i$io" using io-function, file-io,                               open-mode, logical-info        if return-code = 0       display message "I$IO Error: open : " F_ERRNO     else       move return-code to f    end-if. get-record-count.    set info-function to true    set get-record-count to true    call "I$IO" using io-function, f, info-mode,                       record-count-info close-file.    set close-function to true    call "i$io" using io-function  f         giving returnCode    if returnCode = 0       display message "I$IO Error: close : " F_ERRNO     end-if.