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opaque handle?

James Du
Ranch Hand

Joined: Mar 23, 2001
Posts: 186
Hi,
Here is the description about FileDescriptor in the API, could anyone kindly tell me what does the word opaque mean here?

Instances of the file descriptor class serve as an opaque handle to the underlying machine-specific structure representing an open file, an open socket, or another source or sink of bytes. The main practical use for a file descriptor is to create a FileInputStream or FileOutputStream to contain it.

Thanks
James
Cindy Glass
"The Hood"
Sheriff

Joined: Sep 29, 2000
Posts: 8521
OPAQUE means "solid colored", the opposite of transparent.
From the API for interface Transparent:
static int OPAQUE
Represents image data that is guaranteed to be completely opaque, meaning that all pixels have an alpha value of 1.0.


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William Brogden
Author and all-around good cowpoke
Rancher

Joined: Mar 22, 2000
Posts: 12268
    
    1
I am guessing that they mean that although FileDescriptor contains data about the underlying operating system handle, you the programmer can't get at it and directly manipulate it.
Bill

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Cindy Glass
"The Hood"
Sheriff

Joined: Sep 29, 2000
Posts: 8521
DUH Guess that I should read past the obvious to the real meaning. Thanks Bill.
James Du
Ranch Hand

Joined: Mar 23, 2001
Posts: 186
Thaks all, through i still dont quite understand that.
kaushik banerjee
Ranch Hand

Joined: Mar 11, 2001
Posts: 56
Hi James,
The opaque handle they are talking about is the spl property of the FileDescriptor class . An object of this class allows u to twidle with implementation-specific things in an unique way without u bothering about the effect has been brought about,ie the File Descriptor object automatically connects to the handle reqd 2 perform the task on the object u are working with it without u passing the intricacies of it to the File Descriptor object. Hope this helps
Regards,
Kaushik
 
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