Reports whether a pointer is a valid window pointer.

Boolean IsValidWindowPtr (
    GrafPtr grafPort
);

grafPort

A pointer to a graphics port. You pass the pointer to be examined.

function result

true if the specified pointer is a valid window pointer; otherwise, false.

DISCUSSION

A custom control definition may use the IsValidWindowPtr function to determine whether it is being asked to draw onscreen or offscreen.

This function is primarily intended for use with debugging your application.

SPECIAL CONSIDERATIONS

The IsValidWindowPtr function is a processor-intensive call.

VERSION NOTES

This function is available with Mac OS 8.5 and later.

AVAILABILITY

Supported in Carbon. Available in CarbonLib 1.0 and later when WindowsLib 8.5 or later is installed. Exported by CarbonLib 1.0 and later and by WindowsLib 8.5 and later.

© 2000 Apple Computer, Inc. — (Last Updated 4/14/2000)