# ID Specifier (ID=)

The ID specifier identifies a pending data transfer operation for a specified unit. It takes the following form:

ID=id-var

id-var | Is a scalar integer variable to be used as an identifier. This specifier can only be used if the value of ASYNCHRONOUS=i-expr is 'YES'.

If an ID specifier is used in a data transfer statement, a wait operation is performed for the operation. If it is omitted, wait operations are performed for all pending data transfers for the specified unit.

If an error occurs during the execution of a data transfer statement containing an ID specifier, the variable specified becomes undefined.

In an INQUIRE statement, the ID= specifier identifies a pending asynchronous data transfer. It is is used with the PENDING specifier to determine whether a specific asynchronous pending data transfer is completed.

Parent topic: I/O Control List