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Q246304: Debugging Ported Code

Article: Q246304
Product(s): Microsoft Windows NT
Version(s): 2.2.1,2.2.2,2.2.3,2.2.4
Operating System(s): 
Keyword(s): kbenv
Last Modified: 24-OCT-2000

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The information in this article applies to:

- Interix versions 2.2.1, 2.2.2, 2.2.3, 2.2.4 
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SUMMARY
=======

When debugging ported code, there are several behavioral differences between
Interix and traditional systems like Solaris.

Some users porting code notice that their application memory faults more often
than it did on the original platform. This is usually a result of defects in the
code, and not in the Interix subsystem.

A common cause of this behavior is trying to dereference an uninitialized
pointer. An uninitialized pointer contains some random bit pattern. An attempt
to read or write to that location will succeed or fail depending on whether the
user is permitted access to that address. If the attempt fails, it fails with a
segment fault. If it succeeds, it may cause problems for other programs using
that memory space.

In Microsoft Windows NT 4.0, most of the four-gigabyte address space is off
limits to the user program. Any attempt to read or write to this space causes
the segmentation violation.

MORE INFORMATION
================

The third-party products discussed in this article are manufactured by vendors
independent of Microsoft; we make no warranty, implied or otherwise, regarding
these products' performance or reliability.

For a more complete description of this issue, see the "Porting Applications in
C" Tech Note topic at the following Interix Web site:

  http://www.interix.com/newinterix/main_technotes.htm

Additional query words:

======================================================================
Keywords          : kbenv 
Technology        : kbInterixSearch kbUNIXSearch kbInterix221 kbInterix222 kbInterix223 kbInterix224
Version           : :2.2.1,2.2.2,2.2.3,2.2.4
Issue type        : kbinfo

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