Open Watcom FORTRAN 77 Language Reference

FORTRAN Statements
BLANK = blnk
blnk is a character expression whose value when trailing blanks are removed is ’NULL’
or ’ZERO’. If ’NULL’ is specified then all blank characters in numeric formatted input
fields are ignored except that an entirely blank field has a value of zero. If ’ZERO’ is
specified then all blank characters other than leading blanks are treated as zeroes. If this
specifier is omitted then ’NULL’ is assumed. This specifier may only be present for a file
being connected for formatted input/output.
ACTION = act
act is a character expression whose value when trailing blanks are removed is ’READ’,
’WRITE’ or ’READWRITE’. If ’READ’ is specified, data can only be read from the
file. If ’WRITE’ is specified, data can only be written to the file. If ’READWRITE’ is
specified, data can both be read and written. The default is ’READWRITE’.
CARRIAGECONTROL = cc
cc is a character expression whose value when trailing blanks are removed is ’YES’, or
’NO’. If ’YES’ is specified, Open Watcom FORTRAN 77 will automatically add an
extra character at the beginning of each record. This character will be interpreted as a
carriage control character. If ’NO’ is specified, records will be written to the file without
adding a carriage control character at the beginning of the record. The default is ’NO’.
RECORDTYPE = rct
rct is a character expression whose value when trailing blanks are removed specifies the
type of record (or record structure) to be used for the file. The allowed values for rct
depend on the system on which you are running the program. See the compiler User’s
Guide for a discussion of the RECORDTYPE= specifier.
BLOCKSIZE = bl
bl is an integer expression whose value specifies the internal buffer size to be used for file
input/output. The allowed values for bl depend on the system on which you are running
the program. Generally, the larger the buffer, the faster the input/output. See the compiler
User’s Guide for a discussion of the BLOCKSIZE= specifier.
SHARE = shr
shr is a character expression whose value when trailing blanks are removed specifies the
way in which other processes can simultaneously access the file. The allowed values for
shr depend on the system on which you are running the program. See the compiler User’s
Guide for a discussion of the SHARE= specifier.
Example:
OPEN( UNIT=1, FILE=’TEST’, STATUS=’UNKNOWN’,
+ ACCESS=’SEQUENTIAL’,
+ FORM=’FORMATTED’, BLANK=’ZERO’ )
In the above example, the file ’TEST’, containing FORMATTED records, is connected to unit 1. The
status of the file is ’UNKNOWN’ since we do not know if it already exists. We will access the file
sequentially, using formatted input/output statements. Blanks in numeric input data are to be treated as
zeroes.
OPEN Statement 113