OPEN Statement Overview

The OPEN statement connects an external file to a unit, creates a new file and connects it to a unit, creates a preconnected file, or changes certain properties of a connection. For more information, see OPEN.

The following table summarizes the OPEN statement specifiers (and contains links to their descriptions):

OPEN Statement Specifiers and Values

Specifier Values Function Default
ACCESS 'SEQUENTIAL'
'DIRECT'
'APPEND'
Access mode 'SEQUENTIAL'
ACTION
(or MODE)
'READ'
'WRITE'
'READWRITE'
File access 'READWRITE'
ASSOCIATEVARIABLE var Next direct access record No default
ASYNCHRONOUS 'YES'
'NO'
Asynchronous I/O 'NO'
BLANK 'NULL'
'ZERO'
Interpretation of blanks 'NULL'
BLOCKSIZE n_expr Physical block size Filesystem default
BUFFERCOUNT n_expr Number of I/O buffers One
BUFFERED 'YES'
'NO'
Buffering for WRITE operations 'NO'
CARRIAGECONTROL 'FORTRAN'
'LIST'
'NONE'
Print control Formatted: 'LIST' 1
Unformatted: 'NONE'
CONVERT 'LITTLE_ENDIAN'
'BIG_ENDIAN'
'CRAY'
'FDX'
'FGX'
'IBM'
'VAXD'
'VAXG'
'NATIVE'
Numeric format specification 'NATIVE'
DEFAULTFILE c_expr Default file pathname Current working directory
DELIM 'APOSTROPHE'
'QUOTE'
'NONE'
Delimiter for character constants 'NONE'
DISPOSE
(or DISP)
'KEEP' or 'SAVE'
'DELETE'
'PRINT'
'PRINT/DELETE'
'SUBMIT'
'SUBMIT/DELETE'
File disposition at close 'KEEP'
ERR label Error transfer control No default
FILE
(or NAME)
c_expr File pathname (file name) fort.n 2
FORM 'FORMATTED'
'UNFORMATTED'
'BINARY'
Format type Depends on ACCESS setting
IOFOCUS .TRUE.
.FALSE.
Active window in QuickWin application .TRUE.3
IOSTAT var I/O status No default
MAXREC n_expr Direct access record limit No limit
NOSHARED 4 No value File sharing disallowed L*X, M*X: SHARED
W*32, W*64: Not shared
ORGANIZATION 'SEQUENTIAL'
'RELATIVE'
File organization 'SEQUENTIAL'
PAD 'YES'
'NO'
Record padding 'YES'
POSITION 'ASIS'
'REWIND'
'APPEND'
File positioning 'ASIS'
READONLY No value Write protection No default
RECL
(or RECORDSIZE)
n_expr Record length Depends on RECORDTYPE, ORGANIZATION, and FORM settings 5
RECORDTYPE 'FIXED'
'VARIABLE'
'SEGMENTED'
'STREAM'
'STREAM_CR'
'STREAM_LF'
Record type Depends on ORGANIZATION, CARRIAGECONTROL, ACCESS, and FORM settings
SHARE 4 'DENYRW'
'DENYWR' 6
'DENYRD' 6
'DENYNONE'
File locking 'DENYWR' 7
SHARED 4 No value File sharing allowed L*X, M*X: SHARED
W*32, W*64: Not shared
STATUS (or TYPE) 'OLD'
'NEW'
'SCRATCH'
'REPLACE'
'UNKNOWN'
File status at open 'UNKNOWN' 8
TITLE c_expr Title for child window in QuickWin application No default
UNIT n_expr Logical unit number No default; an io-unit must be specified
USEROPEN func User program option No default
1 If you use the compiler option specifying OpenVMS defaults, and the unit is connected to a terminal, the default is 'FORTRAN'.
2 n is the unit number.
3 If unit '*' is specified, the default is .FALSE.; otherwise, the default is .TRUE..
4 For information on file sharing, see Building Applications.
5 On Linux* and Mac OS* X systems, the default depends only on the FORM setting.
6 W*32, W*64
7 The default differs under certain conditions (see SHARE Specifier).
8 The default differs under certain conditions (see STATUS Specifier).
Key to Values
   c_expr: A scalar default character expression
   func:   An external function
   label:  A statement label
   n_expr: A scalar numeric expression
   var:    A scalar integer variable
   

See Also