# The Concurrent ML Reference Manual

## The `OS.IO` structure

#### Synopsis

> `signature `CML_OS_IO`
> structure `IO` : CML_OS_IO
> `

The OS.IO structure provides a general interface for polling I/O devices, which has been modelled after the Unix SVR4 poll interface. A poll_desc, created from an I/O descriptor, can be used to test for various polling conditions.

#### Interface

> `include OS_IO
> val pollEvt : poll_desc list -> poll_info list event
> `

#### Description

`pollEvt l`
  polls a list of poll descriptors l. This will raise OS.SysErr if, for example, one of the file descriptors refers to a closed file.

#### See Also

> OS, OS.IO

[ Top | Parent | Contents | Index | Root ]

Last Modified &date;
Comments to John Reppy.
Copyright © 1998 Bell Labs, Lucent Technologies