INQUIRE

Statement: Returns information on the status of specified properties of a file, logical unit, or directory. It takes one of the following forms:

Inquiring by File:

INQUIRE (FILE=name[, ERR=label] [, ID=id-var] [, IOMSG=msg-var] [, SIZE=sz] [, IOSTAT=i-var] [, DEFAULTFILE=def] slist)

Inquiring by Unit:

INQUIRE ([UNIT=]io-unit [, ERR=label] [, ID=id-var] [, IOMSG=msg-var] [, SIZE=sz] [, IOSTAT=i-var] slist)

Inquiring by Directory:

INQUIRE (DIRECTORY=dir, EXIST=ex [, DIRSPEC=dirspec] [, ERR=label] [, ID=id-var] [, IOMSG=msg-var] [, SIZE=sz] [, IOSTAT=i-var])

Inquiring by Output List:

INQUIRE (IOLENGTH=len) out-item-list

name

Is a scalar default character expression specifying the name of the file for inquiry. For more information, see FILE Specifier and STATUS Specifier.

label

Is the label of the branch target statement that receives control if an error occurs. For more information, see Branch Specifiers.

id-var

Is a scalar integer expression identifying a data transfer operation that was returned using the ID= specifier in a previous asynchronous READ or WRITE statement. For more information, see ID Specifier.

msg-var

Is a scalar default character variable that is assigned an explanatory message if an I/O error occurs. For more information, see I/O Message Specifier.

Is a scalar integer variable that is assigned the size of the file in file storage units. For more information, see Size Specifier.

i-var

Is a scalar integer variable that is defined as a positive integer if an error occurs and zero if no error occurs. For more information, see I/O Status Specifier.

def

Is a scalar default character expression specifying a default file pathname string. (For more information, see the DEFAULTFILE specifier.)

slist

Is one or more of the following inquiry specifiers (each specifier can appear only once):

ACCESS	DELIM	NEXTREC	RECL
ACTION	DIRECT	NUMBER	RECORDTYPE
ASYNCHRONOUS	ENCODING	OPENED	ROUND
BINARY	EXIST	ORGANIZATION	SEQUENTIAL
BLANK	FORM	PAD	SHARE
BLOCKSIZE	FORMATTED	PENDING	SIGN
BUFFERED	IOFOCUS	POS	SIZE
CARRIAGECONTROL	MODE	POSITION	UNFORMATTED
CONVERT	NAME	READ	WRITE
DECIMAL	NAMED	READWRITE

io-unit

Is an external unit specifier.

The unit does not have to exist, nor does it need to be connected to a file. If the unit is connected to a file, the inquiry encompasses both the connection and the file.

dir

Is a scalar default character expression specifying the name of the directory for inquiry. If you are inquiring by directory, it must be present.

Is a scalar default logical variable that is assigned the value .TRUE. if dir names a directory that exists; otherwise, ex is assigned the value .FALSE.. If you are inquiring by directory, it must be present. For more information, see the EXIST Specifier.

dirspec

Is a scalar default character variable that is assigned the value of the full directory specification of dir if ex is assigned the value .TRUE.. This specifier can only be used when inquiring by directory.

len

(Output) Is a scalar integer variable that is assigned a value corresponding to the length of an unformatted, direct-access record resulting from the use of the out-item-list in a WRITE statement.

The value is suitable to use as a RECL specifier value in an OPEN statement that connects a file for unformatted, direct access.

The unit of the value is 4-byte longwords, by default. However, if you specify compiler option assume byterecl, the unit is bytes.

out-item-list

(Output) Is a list of one or more output items (see I/O Lists).

Description

The control specifiers ([UNIT=] io-unit, ERR= label, and IOSTAT= i-var) and inquiry specifiers can appear anywhere within the parentheses following INQUIRE. However, if the UNIT keyword is omitted, the io-unit must appear first in the list.

An INQUIRE statement can be executed before, during, or after a file is connected to a unit. The specifier values returned are those that are current when the INQUIRE statement executes.

To get file characteristics, specify the INQUIRE statement after opening the file.

Example

The following are examples of INQUIRE statements:

INQUIRE (FILE='FILE_B', EXIST=EXT)
INQUIRE (4, FORM=FM, IOSTAT=IOS, ERR=20)
INQUIRE (IOLENGTH=LEN) A, B

In the last statement, you can use the length returned in LEN as the value for the RECL specifier in an OPEN statement that connects a file for unformatted direct access. If you have already specified a value for RECL, you can check LEN to verify that A and B are less than or equal to the record length you specified.

The following shows another example:

!    This program prompts for the name of a data file.
!    The INQUIRE statement then determines whether
!    the file exists. If it does not, the program
!    prompts for another file name.

      CHARACTER*12 fname
      LOGICAL exists

!     Get the name of a file:
100   WRITE (*, '(1X, A\)') 'Enter the file name: '
      READ (*, '(A)') fname

!     INQUIRE about file's existence:
      INQUIRE (FILE = fname, EXIST = exists)

      IF (.NOT. exists) THEN
        WRITE (*,'(2A/)') ' >> Cannot find file ', fname
        GOTO 100
      END IF
      END

INQUIRE

Description

Example

See Also