Manual Reference Pages - close (7)
NAME
CLOSE(7f) - [FORTRAN:IO] terminate the connection of a specified unit to an external file. (LICENSE:PD)
SYNOPSIS
CLOSE ( [UNIT= ] file-unit-number, [IOSTAT= scalar-int-variable,]
[IOMSG= iomsg-variable,] [ERR= label,] [STATUS= scalar-default-char-expr])
DESCRIPTION
The CLOSE statement is used to terminate the connection of a specified unit to an external file.
Execution of a CLOSE statement for a unit may occur in any program unit of a program and need not occur in the same program unit as the execution of an OPEN statement referring to that unit.
Execution of a CLOSE statement performs a wait operation for any pending asynchronous data transfer operations for the specified unit.
Execution of a CLOSE statement specifying a unit that does not exist or has no file connected to it is permitted and affects no file or unit.
After a unit has been disconnected by execution of a CLOSE statement, it may be connected again within the same program, either to the same file or to a different file. After a named file has been disconnected by execution of a CLOSE statement, it may be connected again within the same program, either to the same unit or to a different unit, provided that the file still exists.
The input/output statements are the OPEN, CLOSE, READ, WRITE, PRINT, BACKSPACE, ENDFILE, REWIND, FLUSH, WAIT, and INQUIRE statements.
OPEN, CLOSE, BACKSPACE, ENDFILE, and REWIND statements shall not be executed while a parent data transfer statement is active.
A pure subprogram shall not contain a print-stmt, open-stmt, close-stmt, backspace-stmt, endfile-stmt, rewind-stmt, flush-stmt, wait-stmt, or inquire-stmt.
The READ statement is a data transfer input statement. The WRITE statement and the PRINT statement are data transfer output statements. The OPEN statement and the CLOSE statement are file connection statements. The INQUIRE statement is a file inquiry statement. The BACKSPACE, ENDFILE, and REWIND statements are file positioning statements.
All input/output statements may refer to files that exist. An INQUIRE, OPEN, CLOSE, WRITE, PRINT, REWIND, FLUSH, or ENDFILE statement also may refer to a file that does not exist. Execution of a WRITE, PRINT, or ENDFILE statement referring to a preconnected file that does not exist creates the file. This file is a different file from one preconnected on any other image.
AT PROGRAM TERMINATION
During the completion step of termination of execution of a program, all units that are connected are closed. Each unit is closed with status KEEP unless the file status prior to termination of execution was SCRATCH, in which case the unit is closed with status DELETE.
The effect is as though a CLOSE statement without a STATUS= specifier were executed on each connected unit.
OPTIONS
No specifier shall appear more than once in a given close-spec-list.
UNIT=file-unit-number A file-unit-number shall be specified in a close-spec-list; if the optional characters UNIT= are omitted, the file-unit-number shall be the first item in the close-spec-list. IOSTAT=scalar-int-variable 0 means no error occurred IOMSG=iomsg-variable Character variable to hold message if an error occurred. ERR=label The label used in the ERR= specifier shall be the statement label of a branch target statement that appears in the same scoping unit as the CLOSE statement. STATUS=scalar-default-char-expr The expression has a limited list of character values. Any trailing blanks are ignored. The value specified is without regard to case. The scalar-default-char-expr shall evaluate to KEEP or DELETE. The STATUS= specifier determines the disposition of the file that is connected to the specified unit. KEEP shall not be specified for a file whose status prior to execution of a CLOSE statement is SCRATCH. If KEEP is specified for a file that exists, the file continues to exist after the execution of a CLOSE statement. If KEEP is specified for a file that does not exist, the file will not exist after the execution of a CLOSE statement. If DELETE is specified, the file will not exist after the execution of a CLOSE statement. If this specifier is omitted, the default value is KEEP, unless the file status prior to execution of the CLOSE statement is SCRATCH, in which case the default value is DELETE.
EXAMPLE
sample program:
program demo_close implicit none character(len=256) :: message integer :: ios open (10, file=’employee.names’, action=’read’, iostat=ios,iomsg=message) if (ios < 0) then ! perform end-of-file processing on the file connected to unit 10.close (10, status=’keep’,iostat=ios,iomsg=message) if(ios.ne.0)then write(*,’(*(a))’)’*demo_close* close error: ’,trim(message) stop 1 endif elseif (ios > 0) then ! perform error processing on open write(*,’(*(a))’)’*demo_close* open error: ’,trim(message) stop 2 endif end program demo_close
| close (7) | March 11, 2021 |
