f_offset

Sergey Babkin babkin at verizon.net
Mon Apr 14 15:18:25 UTC 2008


>From: Poul-Henning Kamp <phk at phk.freebsd.dk>

>In message <20080414145231.GJ5934 at hoeg.nl>, Ed Schouten writes:
>
>>It's all so confusing that the standards seem to change then. When I
>>take a look at the POSIX onlinepubs, the articles seem to mention the
>>opposite:
>>
>>http://www.opengroup.org/onlinepubs/009695399/functions/read.html
>>
>>	"The behavior of multiple concurrent reads on the same pipe,
>>	FIFO, or terminal device is unspecified."
>>
>>http://www.opengroup.org/onlinepubs/009695399/functions/write.html
>>
>>	"This volume of IEEE Std 1003.1-2001 does not specify behavior
>>	of concurrent writes to a file from multiple processes.
>>	Applications should use some form of concurrency control."
>
>Remember that POSIX was written so both MVS and Windows could comply,

And nowadays Linux too :-)

>UNIX may have and need higher standards.

Yep. Linux in this respect is not Unix. This behavior of Linux is 
pretty annoying (the log files get mixed up pretty badly) 
but I agree that it makes the writes on the highly contested files
faster.

-SB


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