Bigarray.*.map_file

Bigarray.*.map_file

[Bauer, Christoph]

Hi,

Bigarray.Genarray.map_file uses mmap to "read" a file. How can
I specify an offset in the file (like the offset parameter in mmap)?
Unix.lseek doesn't help me.

How can I do an munmap? I ask because of these lines from the man-page:

       The munmap system call deletes the mappings for the speci-
       fied address  range,  and  causes  further  references  to
       addresses within the range to generate invalid memory ref-
       erences.  The region is also automatically  unmapped  when
       the process is terminated.  On the other hand, closing the
       file descriptor does not unmap the region.

Thanks,

Christoph Bauer
Dipl. Inf.

LMS Deutschland GmbH
Luxemburgerstr. 7
D-67657 Kaiserslautern

T +49 631 303 22 152

mailto:Christoph.Bauer@lms-gmbh.de
http://www.lmsintl.com 

Re: [Caml-list] Bigarray.*.map_file

[Olivier Andrieu]

Hi,

 Bauer, Christoph [Wednesday 14 September 2005] :
 > Bigarray.Genarray.map_file uses mmap to "read" a file. How can
 > I specify an offset in the file (like the offset parameter in mmap)?
 > Unix.lseek doesn't help me.

You can't: mmap is called with offset 0 (see
otherlibs/bigarray/mmap_unix.c). 

 > How can I do an munmap? I ask because of these lines from the man-page:
 > 
 >        The munmap system call deletes the mappings for the speci-
 >        fied address  range,  and  causes  further  references  to
 >        addresses within the range to generate invalid memory ref-
 >        erences.  The region is also automatically  unmapped  when
 >        the process is terminated.  On the other hand, closing the
 >        file descriptor does not unmap the region.

unmap() is called when the bigarray is collected by the GC.

-- 
   Olivier