The I/O status specifier designates a variable to store a value indicating the status of I/O operations. It takes the following form:
IOSTAT = ios
Execution of an I/O statement containing this specifier defines the variable (ios) as one of the following:
If an error or end-of-file condition occurs, ios is set and execution continues with the statement after the I/O termination.
For details on the error numbers returned by IOSTAT, see your user manual.