HP 3000 Manuals HP 3000 Manuals
How the File System Closes a File
You terminate access to a file from your program with the FCLOSE
intrinsic. The FCLOSE intrinsic applies to both disk and device files.
FCLOSE also deallocates the device on which the file resides; however, if
your program has several concurrent HPFOPEN/FOPEN calls issued to the
same file, the device is not deallocated until the last "nested" FCLOSE
intrinsic is executed.
You can use the FCLOSE intrinsic to specify (or change) the disposition
of a disk or a magnetic tape file when it is closed. The disposition of
a disk or magnetic tape file can be new, temporary, or permanent. If you
do not change the disposition of a new file when it is closed, the file
and its contents are deleted from the system when the file is closed
using FCLOSE.
You can change the disposition of a new file to be either temporary or
permanent. A file closed with a temporary disposition is closed as a
temporary file. It is deleted from the system when your job/session is
terminated. A file closed with a permanent disposition is closed and
saved as a permanent file. It remains in the system domain after your
job/session ends, and until you purge it.
When you close a file with either a temporary or permanent disposition,
MPE/iX conducts a search:
* If the file is to be closed as a temporary file, the job file
domain is searched .
* If the file is to be closed as a permanent file, the system file
domain is searched .
You are not allowed to have duplicate file names in the same domain. If
MPE/iX finds a file of the same name in the searched directory, the file
is not closed, and the FCLOSE intrinsic returns an error condition.
You can specify the disposition of a file when it is opened when you use
the final disposition option or the file equation option of the HPFOPEN
intrinsic, or the FILE command. Both HPFOPEN options provides the same
choices as the disposition parameter of FCLOSE, except that you can
change the disposition of a file when the file is opened (as opposed to
when the file is closed). For more information about HPFOPEN options,
refer to the MPE/iX Intrinsics Reference Manual (32650-90028).
NOTE Even though you are allowed to specify a file's final disposition
when the file is opened, MPE/iX does not search the appropriate
directory until you attempt to close that file.
If a conflict occurs between the dispositions specified at file-open time
and file-close time, the disposition specification that has the lower
positive-integer value takes precedence. For example, if a disposition
of temporary (final disposition option = 2) is specified by HPFOPEN, and
a disposition of permanent (disposition = 1) is specified by FCLOSE , the
disposition specified by FCLOSE takes precedence. Likewise, if there are
conflicts between the disposition specifications of multiple FCLOSE calls
on the same file, the disposition specification that has the lower
positive-integer value takes precedence when the file is finally closed.
If your program does not issue an FCLOSE intrinsic call on files that
have been opened, MPE/iX closes all files automatically when the
program's process terminates. In this case, MPE/iX closes all opened
files with the same disposition they had before being opened. New files
are deleted; old files are saved and assigned to the domain in which they
belonged previously, either permanent or temporary; however, if you
specified the file's disposition when you opened it with HPFOPEN, that
disposition takes effect.