206) Why do I get so many uninitilized memory read (UMR) errors when

I run Purify[tm] on my Motif programs?
[Last modified: July 96]

Answer: Purify's reports are suggestions and do not always indicate real bugs.
The X libraries frequently allocate dynamic memory, e.g., for attribute or
event structures, but don't explicitly initialize all of the memory.  X keeps
track of which structure fields are valid via a union type or a mask.  When X
tries to copy or write the memory (part of which is uninitialized) as one
block, Purify reports a UMR.  This is not a bug and you can safely supress or
ignore the report.  Yes, X could initialize the unused field, but since this
happens alot, the needless operation could negatively affect your performance.

Ken Lee

Top Document: Motif FAQ (Part 6 of 9)
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Last Update July 24 2008 @ 00:14 AM