traversal_lock(3G)

NAME

traversal_lock − control display locking during display list traversal

SYNOPSIS

C Syntax

void traversal_lock(fildes, lock)
int fildes, lock;

FORTRAN77 Syntax

subroutine traversal_lock(fildes, lock)
integer*4 fildes, lock

Pascal Syntax

procedure traversal_lock(fildes, lock:integer);

DESCRIPTION

Input Parameters

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

lock Controls whether to lock the display during display and pick traversal. TRUE (1) causes locking. FALSE (0) does not.

Discussion

Traversal_lock controls locking of the display during traversal of the display list on fildes. Locking the display for the entire traversal time can improve performance of display and pick operations. The traversal operations affected are those initiated by the following routines: display_segment(3G), display_segment_hsr(3G), refresh_segment(3G), refresh_segment_hsr(3G), and pick_from_segment(3G). All other display updates are deferred until the traversal is complete. Output cannot be sent to terminal emulators and window systems. Signal handling is also suspended during traversal.

ERRORS

1 Graphics device is not initialized for this operation.

HARDWARE DEPENDENCIES

Traversal locking improves performance on the HP 98721 devices only.

DEFAULTS

The default is FALSE (0): do not lock for entire traversal.

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