INQUIRE_REQUEST_STATUS(3G)

NAME

inquire_request_status − inquire status of a request to an input device

SYNOPSIS

C Syntax:

void inquire_request_status(fildes,class,ordinal,ready);
int fildes,class,ordinal,*ready

FORTRAN77 Syntax:

subroutine inquire_request_status(fildes,class,ordinal,ready)
integer*4 fildes,class,ordinal,ready

Pascal Syntax:

procedure inquire_request_status(fildes,class,
ordinal:integer;var ready:integer);

DESCRIPTION

Input Parameters

fildes Integer file descriptor returned by gopen when an I/O path to a graphics device is opened.

class One of the defined values, LOCATOR, CHOICE or ALL.

ordinal Logical device number ranging from 1 to number of devices in this class.

OUTPUT PARAMETER

ready Set to TRUE (1) if there is a request ready but not yet read.

Discussion

Inquire_request_status returns the status of a pending request for the device named by fildes, class, and ordinal. If class is set to ALL, ordinal is ignored and ready returns the logical OR of ready for each logical device associated with this fildes.

Ready returns TRUE (1) if there a request is ready but not yet read, and FALSE (0) if there is no request pending or the request pending is not ready.

This call can be used to determine (poll) whether a request_choice or request_locator needs to be issued, without halting the calling process to wait for an input.

Museum

Related Articles