12.5 INQUIRE Statement

The INQUIRE statement returns information on the status of specified properties of a file or logical unit. It takes one of the following forms:

Inquiring by File

 INQUIRE (FILE=name [,ERR=label] [,IOSTAT=i-var] [,DEFAULTFILE=def], slist)

Inquiring by Unit

 INQUIRE ([UNIT=]io-unit [,ERR=label] [,IOSTAT=i-var], slist)

Inquiring by Output List

 INQUIRE (IOLENGTH=len) out-item-list
Is a scalar default character expression specifying the name of the file for inquiry.
Is the label of the branch target statement that receives control if an error occurs.
Is a scalar integer variable that is defined as a positive integer if an error occurs and zero if no error occurs.
Is one or more inquiry specifiers. Each specifier can appear only once. (The inquiry specifiers are described individually in the following sections.)
Is a scalar default character expression specifying a default file name specification string. (For more information on the DEFAULTFILE specifier, see Section 12.6.9.)
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.

Is a scalar default integer variable indicating the number of bytes of data that would result from using out-item-list in an unformatted output statement.
Is a list of one or more output items (see Section 10.2.2).

Rules and Behavior

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 specifier 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.

To inquire about a file using the DEFAULTFILE specifier, the specifier must also appear in the OPEN statement for that file. You can specify DEFAULTFILE=def in addition to (or in place of) FILE=name.


The following are examples of INQUIRE statements:


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.

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