FCLOSE

Table 4-4 FCLOSE disposition Parameter Bit Settings

When a new file is created by FOPEN, the job temporary and system file domains are not searched to determine whether a file of the same name exists already. Only when a file is closed and saved as a permanent or temporary file with FCLOSE, is such a search conducted. The job temporary file domain is searched if the file is closed with the domain field of disposition set to 2 or 3 (save as temporary file); the system file domain is searched if the file is closed with domain set to 1 (save as permanent file). If a file of the same name is found in either directory, an error code is returned. Thus it is possible to open a new file with the same name as an existing file, but an error results if FCLOSE is used to save such a file in the same domain with a file of the same name.

In general, unless you plan to use the file once and then delete it, a newly created file should be closed using FCLOSE with the disposition parameter set to 1, 2, or 3. There is no need to set disposition to 4 in order to delete a new file since a new file is deleted when it is closed with a disposition of 0.

The security code parameter (seccode) is set only when the disposition parameter is set to 1. If you want exclusive access to a file being saved as a new permanent file, you should set seccode to 1 when you close the file for the first time. Otherwise, the file can be accessed by any other user.

In Title not available, a new file is closed and saved as a permanent file in the system file domain (disposition = 1), and access is permitted to the file by other users (seccode = 0).

Unless you plan to change the domain where a file is saved, you usually close an existing file with both FCLOSE parameters set to zero. There are two limitations: you cannot change an existing permanent file to a temporary file, and you cannot change the security code that was assigned to a permanent file at creation.

 



<<**************************************>> 

<<* READ DATA FROM $STDIN DEVICE       *>> 

<<**************************************>> 

L1 : 

READ(INPUT,-72): <<READ ONE RECORD FROM $STDIN>> 

IF > 

THEN BEGIN <<END OF FILE ON $STDIN>> 

  FCLOSE(FILNUM,1,0); <<CLOSE THE KSAM FILE>> 

  IF << THEN 

    BEGIN <<CANNOT CLOSE THE KSAM FILE>> 

       MOVE MESSAGE:="CANNOT CLOSE THE KSAM FILE": 

       PRINT (MESSAGE,-29,0): 

       FCHECK(FILNUM,ERRORCODE): <<GET THE ERROR NUMBER>> 

       FERRMSG(ERRORCODE,MESSAGE,LENGTH):<<GET MESSAGE STRING>> 

       PRINT(MESSAGE,-LENGTH,0)1 <<PRINT ERROR MESSAGE>>

    END; 

  TERMINATE; 

 END; 

IF < 

THEN BEGIN 

  MOVE MESSAGE:="ERROR OCCURRED WHILE READING INPUT"; 

  PRINT(MESSAGE,-34,0); 

  TERMINATE; 

 END; 

PRINT(OUTPUT,-72,0); <<ECHO CHECK>> 

Assume, for example, that a file was closed as a job temporary file. Should you want to make the file permanent, close the file with the following call:

 

    FCLOSE(FILENUM,1,0) close job temporary file as permanent file 

If, however, you want to maintain this file with its cuff ent disposition, you would close it with the following call:

 

    FCLOSE(FILENUM,0,0) close file with current disposition 

Regardless of the value assigned to seccode, the type of security initially applied to the file when it is closed as a new permanent file is not subsequently changed.

The FCLOSE intrinsic can be used to delete a KSAM file from the system. If you intend to use a new file once only, you can delete it at the same time you close it for the first time by setting the FCLOSE parameters to zero:

 

    FCLOSE(FILNUM,0,0) delete a new file 

In this case, because disposition is zero, the file is returned to its domain before FCLOSE is executed. Since the file is not assigned a domain until it is closed the first time, this effectively deletes the file.

A file that has been assigned to a domain by a previous FCLOSE, can be deleted by the call:

 

     FCLOSE(FILNUM,4,0) delete an existing file 

Note that the only other methods for deleting a KSAM file are to use the KSAMUTIL>PURGE command, or to issue two MPE :PURGE commands, one for the data file and one for the key file.