OPEN

 Opens an existing file or creates a new file.  If you do not
 explicitly open a file before accessing it, the file is created
 (for write operations) or opened with default attributes.

    OPEN (par[,par]...)

    par  Is a keyword specification in one of the 
         following forms:

         keywd
         keywd=value

         keywd  Is a keyword.  (See the subtopic headings
                listed at the end of this Help topic.)
         value  Is a keyword value. (Some keywords do not
                have keyword values.)

 If an OPEN statement is executed for a unit that is already open,
 and the file pathname (or specification) is different from that of
 the current open file, the previously opened file is closed and the
 new file is opened.  If the file pathname (or specification) is the
 same for both files, the new value of the BLANK= specifier is in
 effect, but the position of the file is unaffected.

 Keyword specifications can appear in any order.  In most cases,
 they are optional.  Default values apply in their absence.  If the
 logical unit specifier is the first parameter in the list, the UNIT
 keyword is optional.

 You can specify character values at run time by substituting a
 general character expression for a keyword value in the OPEN
 statement.  The character value can contain trailing spaces but not
 leading or embedded spaces; for example:

    CHARACTER*6 FINAL /' '/
    ...
    IF (exp) FINAL = 'DELETE'
    OPEN (UNIT=1, STATUS='NEW', DISP=FINAL)

                                NOTE

         Keyword values that are numeric expressions can  be
         any  integer  or real expression.  The value of the
         expression is converted to integer data type before
         it is used in the OPEN statement.

Additional information available:

ACCESS          ACTION          ASSOCIATEVARIABLE               BLANK
BLOCKSIZE       BUFFERCOUNT     BUFFERED        CARRIAGECONTROL CONVERT
DEFAULTFILE     DELIM           DISPOSE         ERR             EXTENDSIZE
FILE            FORM            INITIALSIZE     IOSTAT          KEY
MAXREC          NAME            NOSPANBLOCKS    ORGANIZATION    PAD
POSITION        READONLY        RECL            RECORDSIZE      RECORDTYPE
SHARED          STATUS          TYPE            UNIT            USEROPEN