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RE: higher-level IO very slow with cygwin1.dll 5.10 (due to set_flags?)


> -----Original Message-----
> From: cygwin-owner On Behalf Of Christopher Faylor
> Sent: 27 June 2004 01:23

> On Sat, Jun 26, 2004 at 10:45:51PM +0100, Mark Thornton wrote:
> >Pierre A. Humblet wrote:
> >
> >>On Sat, Jun 26, 2004 at 01:09:40PM -0400, Christopher Faylor wrote:
> >> 
> >>
> >>>On Sat, Jun 26, 2004 at 12:05:54PM -0400, Pierre A. Humblet wrote:
> >>>   
> >>>
> >>>>Beware, I found this:
> >>>>2000-05-19  DJ Delorie  <dj@cygnus.com>
> >>>>	* libc/include/stdio.h: no getc/putc macros for cygwin; causes
> >>>>	compatibility issues with different dll versions
> >>>>so you may need to recompile when updating cygwin.
> >>>>     
> >>>>
> >>>Also wouldn't that work around the file locks that were 
> ostensibly put
> >>>there for a reason?
> >>>   
> >>>
> >>
> >>That crossed my mind. But there is no file lock in the 
> macro, which is
> >>used by systems other than cygwin. How do they manage it?
> >>I also assume that single threaded programs don't need the lock.
> >> 
> >Is the lock to ensure that normal POSIX append semantics are obtained
> >when two processes are writing to the same file?  Normal win32
> >behaviour would tend to overwrite whatever had been written by the
> >other process
> 
> No.  newlib is supposed to be OS agnostic.  The locks are certainly
> for multi-threaded purposes.
> 
> Anyone who is interested could always ask in the newlib mailing list.
> newlib sourceware org.
> 
> cgf


  Those flockfile calls are part of Tom Pfaff's recent fixes to make stdio
multithread-safe.  Without them you can't even have multiple threads calling
printf at the same time without their outputs corrupting each other.


    cheers, 
      DaveK
-- 
Can't think of a witty .sigline today....


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