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User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)

Description of problem:
When using buffered I/O calls (fopen, fread, fwrite, fclose) to read and 
write files from multithreaded programs, data corruption occurs when run 
on multiprocessor machine. The same program using non-buffered calls 
(open, close, read, write) works fine.

How reproducible:
Always

Steps to Reproduce:
1. Build attached freadtest.cpp program using "g++ freadtest.cpp -o 
freadtest -lpthread"
2. Run freadtest
3. Build readtest.cpp program using "g++ readtest.cpp -o readtest -
lpthread" to see working version using non-buffered calls
	

Actual Results:  In the buffered I/O version, around 3-5% of the time the 
data gets corrupted.

Expected Results:  In the non-buffered I/O version, the data is never 
corrupted.

Additional info: