Previous Page | Next Page

File Access

Using the INFILE Statement

An INFILE statement identifies an external file that contains data that you want to read. It opens the file for input or, if the file is already open, makes it the current input file. This means that subsequent INPUT statements are read from this file until another file is made the current input file.

The following options can be used with the INFILE statement:

FLOWOVER

enables the INPUT statement to go to the next record to obtain values for the variables.

LENGTH=variable

names a variable that contains the length of the current record, where the value is set to the number of bytes used after each INPUT statement.

MISSOVER

prevents reading from the next input record when an INPUT statement reaches the end of the current record without finding values for all variables. It assigns missing values to all values that are expected but not found.

RECFM=N

specifies that the file is to be read in as a pure binary file rather than as a file with record-separator characters. You must use the byte operands (< and >) to get new records rather than separate INPUT statements or the new line operator (/).

STOPOVER

stops reading when an INPUT statement reaches the end of the current record without finding values for all variables in the statement. It treats going past the end of a record as an error condition, triggering an end-of-file condition. The STOPOVER option is the default.

The FLOWOVER, MISSOVER, and STOPOVER options control how the INPUT statement works when you try to read past the end of a record. You can specify only one of these options. Read these options carefully so that you understand them completely.

The following example uses the INFILE statement with a FILENAME statement to read the class data file. The MISSOVER option is used to prevent reading from the next record if values for all variables in the INPUT statement are not found.

   filename inclass 'user.text.class';
   infile inclass missover;

You can specify the pathname with a quoted literal also. The preceding statements could be written as follows:

   infile 'user.text.class' missover;
Previous Page | Next Page | Top of Page